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pool filter sand changes PH?

35K views 50 replies 7 participants last post by  whitedevil 
#1 ·
i am cycling my 75g tank. i switched to pool filter sand i picked up at ace. the next day my PH went from 8.0 to 8.4.
i tried putting some of the PFS in a tupperware with some water i tested before adding. the next day the water with the sand had a ph of 8.2 while the control water was tested at 8.0.

it seems like the PFS i bought is definetly increasing my ph. has anyone heard of this before?
i thought PFS wasnt suppose to mess with waters chemistry.

anyhow i need to get my ph down before i add fish. any ideas?
i dont want to have to use ph down ever time i do a water change and my water is very soft so stability may be an issue.

i am thinking maybe i can add something to the tank or filters that can gradually bring down my ph.
ideally i would like to get down to 7.0 or so. water from my tap is around 8.0. water in my 75g tank with sand around 8.4.

any idaes?
 
#2 ·
If the sand is actually causing the pH spike then you won't be able to bring it down. Carbonates are being released from the sand as a result of the low pH. Lowering the pH or acidifying the water will cause pH to spike right back up again. Sorry.

Normally swimming pool sand is silicate based, not calcium based. You just bought the wrong stuff.
 
#3 ·
If the sand is actually causing the pH spike then you won't be able to bring it down. Carbonates are being released from the sand as a result of the low pH. Lowering the pH or acidifying the water will cause pH to spike right back up again. Sorry.

Normally swimming pool sand is silicate based, not calcium based. You just bought the wrong stuff.
i dont understand. the stuff i bought is #20 silica sand.
 
#4 ·
I have pool filter sand in my 55. gal tank and I have a PH of 7.5. You should of got your sand from a pool supply store. I paid $10 for a 25 lb bag. The Ace must have gave you the wrong stuff. I was told to get it from a pool suppy store. I have community fish in my tank Glow light tetras, Harlenquen Rasboras, Dwarf rainbows, mollies, bushy nosed plecos, and 1 large angelfish I also had Red cherry shrimp in the tank with no problems with my fish. Maybe it's something you put in the tank like rocks of some sort or wood that could change the ph also. Good Luck.
 
#6 ·
Was this a substrate change? If so, then it is possible that your old substrate was LOWERING your pH somehow. When you changed to the sand, it didn't raise your pH, it just doesn't lower it like your old substrate did. If you were just using plain old made for aquarium gravel before, then this probably isn't the case. I was just presenting a different way of thinking about it...
 
#7 ·
it was a substrate change. the gravel i used did not alter the ph. as a test i tried soaking sand in a plastic container and the ph of that water changed overnight.
it doesnt bother me if i have to get "the right stuff" and dump the sand i have now. its the fact that as far as anyone can tell me the stuff i have now should be ok.
i dont want to try different sand and get the same outcome.
 
#8 ·
I wouldn't try a different sand just yet, it seems like what you bought is the right stuff. I have been trying to research this, but I can't find anything on silica affecting the outgassing of CO2, which seems like a possibility of what is happening. I would do another water test from the tap in a plastic container for pH, then wait for 4-5 days and test again to see if there is any outgassing that occurs naturally. Since you did a one day test with and without sand, it might be that the sand just speeds up the process. I would also test the kH of the tap water and see if it is unusually high for what you tap pH is. It could be that the pH is just catching up with the alkalinity of the water. If it is one of these causes and you put peat moss in your filter to lower your pH, then you will run the risk of stressing your fish at every water change. If you find out that it is your water reacting, then you might want to look into an RO unit if you are really in need of low pH.
 
#10 ·
the water im using is filtered thru a water softner. i also have a RO unit but it only produces 10g at a time. i just checked again and the PH has seemingly lowered in both my test sample and the tank.



the left is my tank the middle is the test water with sand and the right is the tap. unfortunately my softner went thru a cleaning cycle last night and the ph has been altered. but the sand waters have definetly gone down overnight. they use to have a purple tinge in the indicator. the color i got in the pic is exactly what the tap was yesterday.i think i will be ok. i usually do wc right after my softner cycles, so i get the lowest ph possible from the tap. im am not planning on getting any super sensitive fish, just some tetras, cories, rasboras, and maybe a couple of plecos.

i have to go to work now. i am going to set up a third sand test with the new ph from the tap, just for fun. ill see how it goes when i get home.
 
#9 ·
Were it me,(and it ain't) I would go ahead and let the maturing or (cycling) happen with the current substrate. It is not uncommon for pH shifts to take place during this time. In any event, pH will need to be stable before any attempts at adjusting are made. I would also think that a rise from 8.0 to 8.4 after water has set (off gassed) would not be uncommon.IMHO.
 
#11 ·
I thought that my tap water was hard. Your's is harder then mine. The ph out of my tap is about 7.5. I tested my 55 and the ph is 7.6 it comes out a light blue with the API test kit. Good luck in adjusting your ph. I hope it all works out for you. Post your outcome.
 
#12 ·
actually my water is ultra-soft. 0 GH. also be aware that i am using the API high range PH test.


ok this is the results of the test i ran this morning. left was the tank, middle was my sand test, right is my tap PH but due to my water softner cycling it is different than the water i used in the tank and sand test.



this is the test after i got home from work. left is the tank, next is a new sand test i started that morning, next is the old sand test (same as other pic), then there is the tap test in high range and normal.


what is really weird is that my tank ph has changed alot. went from brown to purple (did it twice to verify). the only thing i did when i got home was to dose with ammonia. could the ammonia have caused the ph difference?

the other results seem ok. my first sand test seems to be about the same if not a little lower. and my new sand test seems to be on the rise.

just really concerned about my tank having such a drastic change, when the only thing i did was add my 24hr ammonia dose.

i guess i will wait till tomorrow morning and see what the tank ph looks like then. maybe once the ammonia is processed the ph will drop again.
 
#13 ·
I noticed that you said your water went through a softener that gives it a gH of 0. I would be curious as to what your kH is. It is possible that your softener is capable of producing a low gH without actually removing any of the bicarbonate that is measured in kH. It is possible that your water is going through a ping pong effect before it reaches a stable pH after coming out of the softener. I really am just guessing at this point though...

:dunno:
 
#14 ·
i know i have a gh of 0. it gets tested by the ws rep all the time. i will look into the kh.



ran a ph test this morning. left is the tank right is the latest sand test. the tank ph is back to normal levels. the only thing i can think of is that the ammonia somehow short circuits the ph test. when i get home tonight i am going to test again before dosing ammonia and right after, and see if there is a difference.
 
#15 ·
I see two very significant issues here.

First, in other parts of this (or another) forum, aquarists who have had experience with household water softeners have warned that they often soften the water by adding stuff and altering the chemical compounds. Without knowing exactly what is happening with the softener, it is very dangerous to be fiddling with the pH in an aquarium. As previous posts have indicated, there are natural buffers in water and nothing you do is going to have a lasting effect if the buffers are acting contrary, but will rather subject the fish to continual pH fluctuations, and that is very bad as I'll explain in a moment (that's the second significant issue).

Chemicals like pH down and similar are not recomended for use in an established aquarium. These chemicals are OK to lower the pH in tap water for a partial water change, but not in an established tank because the natural buffers in the tank water will cause the pH to swing about, depending of course upon the chemical composition of the tank and the tap water and what you're doing. All of this will again stress the fish, and now I'll explain why.

Fish are very closely tied to their environment (the water they live in). Fish "drink" the water they require by osmosis, when the water passes through the cells of the fish. The fish must adjust its internal pH to equal the water coming in, so every pH change in the aquarium causes the fish to adjust its internal pH. In an excellent article on "Fish Growth vs. Tank Size" in the December 2006 issue of TFH, Laura Muha put it very well: "Both salinity and pH affects a fish's growth rate because they affect how hard a fish's body must work to maintain its physiological equilibrium--that is, the complex chain of internal chemical reactions that keep the pH of its blood steady, its tissues fed, and its immune system functioning. When pH and/or salinity stray outside the ideal range for any given species, the fishes' bodies must work harder and use more energy to maintain this equilibrium." Having fluctuating water conditions means the fish is constantly having to adjust its metabolism, and this stresses the fish and can lead to poor health, disease, and even death if not corrected.

The yo-yo effect you are experiencing in your water pH would be very stressful to any fish in such a setup. We need to find out your tap water pH, what pH you want in your tank, and then we can offer suggestions.
 
#16 ·
the problem is not a yo-yo effect.


here are 2 test that were run 10 mins apart.
#1 i ran the test on the left: ph and high range ph.
#2 then added ammonia
#3 ran test on the right: ph and high range ph.
appears that the ammonia messed up the ph test.

i am willing to bet once i no longer have to add ammonia my ph problem will go away.
just never heard of ammonia altering the ph results.

with my current tap ph of 7.4-8.0 i should be ok. my platy tank never had any issues.

the 75g will be a schooling tank, tetras, rainbow fish, and cories.
in a perfect world i would like a ph of 7.0, but i know that probably wont happen with my water.
i thought of adding peat or driftwood, but water changes might cause too much of a swing.

any advice?
 
#18 ·
yeah 7ppm is essentially a zero for this purpose. I have never heard of ammonia affecting pH either, in fact everything that I read says that nothing in the nitrogen cycle has anything to do with pH. Maybe the ammonia you bought isn't quite "pure" like it advertises, but then again what in this world is:). I would just wait for the cycle to finish, then see if you have a stable ph, which I am guessing that you will. Once you do have fish in it, I would recommend that you let your tap water sit for awhile before you use it in your water change to allow any reactions to take place because of the softener that you have on it.
 
#19 ·
yeah 7ppm is essentially a zero for this purpose.
oops my bad, i meant 7dkH which is 125ppm. :oops:

i use the ace brand ammonia, used it when i cycled my 55g. maybe the stuff has a shelf life, it was sitting around for a year before using it in my 75g.
what i would really be interested in knowing is if the ammonia is affecting the ph or just the high range ph test.
good idea about letting the water sit. i am going to talk to my ws rep, see if i can get better stability.

what do you think about my ph and stock? do you think i should add anything physical and try to lower the ph? how would you approach this?
 
#21 ·
Well that changes things. Having anything over ~80ppm is considered a buffering ability. It looks like whatever chemical that the water softener is using is dropping your gH but not your kH. This will create a ping pong effect everytime you do a water change. For the purpose of cycling, I wouldn't change anything until your tank is fully cycled. I would then add peat to your filter for starting an ion exchange that will drop your kH, and subsequently your pH before you add fish. Then the problem comes with water changes. My suggestion would be to prepare the amount of water you will need 2-3 days before your water change and put a large media bag full of peat in there and an airstone for circulation. If you have room somewhere I would suggest a large trash bin or drum of some sort to fill up and have water ready for multiple changes so you don't have to do it every week. I have never had to do this, so someone that has may have a better/easier suggestion.
 
#23 ·
*update*

i just filled my tank with Ro water that had a ph of 6.4. i took out all the pfs washed it throughly and returned half back to the tank. 12 hours later and my tank water went from 6.4 to 7.4. i am testing some sand in unsoftened city water to see if that makes a difference.

it seems like pfs is far from ideal to use as a substrate. somehow it keeps altering my ph. i wanted something soft for my cories but pfs does not seem like a solution.
 
#24 ·
i just tested the ph of the untreated city water with the sand. the ph has gone up just like the softner treated water. whatever is in the sand that affects the ph would do so with whatever type of water i put in. this sand has got to go, and i need to find a suitable replacement.
 
#29 ·
i just bought 2 bags of colorquartz crystal. it is suppose to be guaranteed to be inert. but after a day or so it alters my ph. just like the PFS did. i am so close to just breaking the tank down and selling the parts. i have already spent hundreds on substrates that i cannot use. i dont know what to try now. i have tried RO, softened, and city water all with the same result. i even got a 55g drum in my garage storing RO water, but the tank water just changes ph out of range.
 
#30 ·
This is really weird, but after using the colorquartz crystal and having the same result, it tells me that it wasn't the pfs. Another thing to try is since you have a bunch of RO water in a drum, get two small containers of it and add pfs to one and the colorquartz crystal to the other. Test pH before and a few hours after adding the sand. Run both the normal range and high range tests and make sure that your bottles are not older than 2 years. They have a manufactured date stamped right on the front of them.
 
#31 ·
i have 2 bottles of ph tester and they both test the same......they are kinda old, but i see any expiration or mfg date.the lots are:28A0207 & 28A0607. usually it takes 12 hrs before i see a change in PH. i have tried extensive testing on both substrates. i just set up the same test you recommend also have a third container with some pebbles i had bought at HD. with RO water i havent been doing a high range test. maybe i should give that a try.
i am at a loss if its not the substrate, what could it be? could the PH changes go away with time?
 
#32 ·
I was told that the last four numbers of the lot are the month and year that they are manufactured. If this is true, then you are approaching the two year mark, but they should still be fine. You say that you are at a loss if it is not the substrate, and I say that I am at a loss if it is not the water:shock:. Lets see what the result of the latest tests are, before trying to do anything else.
 
#33 ·
im just lost in general.:cry:
the RO should be the ideal water.....right?
i did do tests with city water with same results. i also took out a sample of RO water and set it next to the other samples.....maybe its enviromental? i will post my results when i get home tomorrow.
 
#34 ·
Well yes the RO SHOULD be ideal water, but if the filters aren't correct for aquarium water, or if the water source has something that we can't test for in it, then RO might not be the answer.


(Wow, run on...:oops:)
 
#35 ·
I've followed this thread, and it is indeed strange. MBilyeu may be correct that there is something in the water source that is so far undetected. I wonder if anyone else on this forum has had this happen?

I would not use a high-range pH kit, I would use a general one. Don't know what this may mean, but as the pH starts out around 6.4 I wuld use a general range kit.

Have you let a container of the RO water stand without anything in it, just a glass full of the water,and tested it the next day to see if the pH changes?
 
#36 ·
I've followed this thread, and it is indeed strange. MBilyeu may be correct that there is something in the water source that is so far undetected. I wonder if anyone else on this forum has had this happen?

I would not use a high-range pH kit, I would use a general one. Don't know what this may mean, but as the pH starts out around 6.4 I wuld use a general range kit.

Have you let a container of the RO water stand without anything in it, just a glass full of the water,and tested it the next day to see if the pH changes?

He should be using both pH tests because if one maxes out, then you are supposed to use the results from the other. The standard test range is from 6.0-7.6 and the high range test is from 7.4-8.8. API breaks it down like this to be more accurate.
 
#37 · (Edited)
OK i have been keeping an excel chart of my values.


HOURS POOL FILTER SAND COLORQUARTZ IN PLASTIC COLORQUARTZ IN GLASS HOME DEPOT PEBBLES WATER CONTROL USED GRAVEL FLOURITE ECO-COMPLETE W/FLOURITE
START 6.6 6.6 6.6 6.6 6.6 XX XX XX
12 HRS 7.0 7.4 7.0 7.0 6.6 6.6 6.6 XX
24 HRS 7.0 7.4 7.4 7.0 6.6 7.4 6.5 6.6


here is my progress. the testees are:
pool filter sand- has been rinsed many times
colorquartz in plastic- has been rinsed many times
coloquartz in glass- just in case the plastic tupperware somehow altered the PH
home depot pebbles- generic pebbles rinsed many times
water control- water in tupperware, nothing else
used gravel- gravel I had laying around from a previous aquarium
flourite- extra flourite taken out of my 55g a year ago
eco-complete w/flourite- just took this sample from my 55g

any ph close or at 7.4 was verified with the high range test.

so far flourite seems to be the favorite. cant wait to see how the eco-complete does.

any ideas or comments?
 
#38 ·
ok here is the chart:


HOURS-- POOL FILTER SAND---- COLORQUARTZ IN PLASTIC-- COLORQUARTZ IN GLASS------- HOME DEPOT PEBBLES------- WATER CONTROL----- USED GRAVEL------ FLOURITE---------ECO-COMPLETE W/FLOURITE
START-------------6.6------------------------------------6.6----------------------------6.6----------------------------6.6---------------------------6.6--------------------xx--------------------XX--------------------XX
12 HRS------------7.0------------------------------------7.4----------------------------7.0----------------------------7.0---------------------------6.6--------------------6.6-------------------6.6-------------------XX
24 HRS------------7.0------------------------------------7.4----------------------------7.4----------------------------7.0---------------------------6.6--------------------7.4-------------------6.5-------------------6.6


anyone know how to copy an excel worksheet so i can post it?
 
#39 ·
Wow, well the numbers don't lie. I still say that it is something in the water that the substrates may be bringing out, but that is just a guess and doesn't matter at this point in time. If you still have everything in the containers I would also do a 48 and 72 hour test.

My personal opinion would be to still use the pfs in your tank if that is the look you want. It doesn't alter your pH an incredible amount, so for water changes I think you will be safe. Just make sure to always use the RO water that you used in the test. Not your original water that put you over 8.0. For almost all fish that are bred in captivity, a pH of 7.0 is near perfect. My 30 gallon community tank has some driftwood in it that brings the pH down from 7.2(tap) to 6.6-6.8. I do 25% weekly water change with no ill effects.
 
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