Ph 6-ish - Water Chemistry Assistance Required
Hi Tropical Fish Keeping Members,
About 6-8weeks ago I finally cycled my 90l tank but yesterday I noticed a Ph problem.
If I'm honest I was only testing the Ph when we first put in the tank and haven't tested it regularly until yesterday because I have read that Ph is misunderstood and actually isn't the important indicator - Gh and Kh are, so long as the Ph is constant and not fluctuating. However, I can say that when I was testing it it was consistently 7.4. Yesterday it was 6.0 or somewhere near that! And obviously 6 is wayyyy to low and going to cause problems if I don't act quick!
I went to my local aquarium store and had the hardness tested and they convinced me that hardness and Ph weren't sufficiently related and to add the Ph Up buffer. The Gh was about 107 and they didn't test the Kh. The aquarium store also said that the Ph was 6.4. But they put their finger over the end of the test tube to shake it and I would have thought that undesirable when testing Ph!
I do have plants in my tank. Originally I had 3 when I first put the tank in, two didn't survive and were removed about a month ago. 1 is still in there. 3 days ago I replaced the dead plants with 3 more. I'm wondering if the plants (not having any Co2 imput or fertiliser) is affecting the hardness?
I had a bit of a snail outbreak in the tank recently and purchased a loach 1 week ago to eat the snails and clean the tank up, which it has done from what I can see. Only a few snails remain in the tank but there are loads of eggs. Is there potential that there are still snails in the tank, or their eggs, are decomposing and causing a high acid level in the tank, causing the low Ph?
Having said that the Ph reading is 6.0 I also tested the water using theAPI high level Ph tester because I was hoping that a reading of 6 meant that the Ph reading was too high for the normal Ph test to read it. The High level Ph test shows a reading of 7.8 but I'm confused about that because the aquarium store said that it was unlikely that it would be that reading and more likely 6.4.????? I have a cheap liquid Ph testing kit that I got when I bought the tank and that is also showing 6.2
Any assistance as to why there has been such a Ph drop from 7.4 originally to 6.(something) would be really appreciated. I've done a fair amount of reading on hardness, but as you can appreciate, it's quite difficult to get a good grasp of when I'm still new to all this fishtank business!:dunno:
Gh: 107 (yesterday before adding conservative amount of aquarium salt yesterday afternoon)
Ph: 6.0 (maybe 7.8????)
Ph of tap water: 7.2
Male Guppies: 4
Bristlenose catfish: 2
Black Phanton Tetras: 4
Clown Loach: 1
Also, what would be considered a low KH value? That is, in a low pH tank, what would you equate the KH value to be? I'm going to get the KH tested and I would like to be able to know roughly what they usually are and what would be considered low.
Some of the store info was a bit off, as I will explain. First thing to understand is that the GH, KH and pH are all related. Depending upon the KH, which number is not given in your posts, the pH may fluctuate. With a GH of 107, which equates to about 6 dGH which is soft, the KH (carbonate hardness, sometimes termed Alkalinity) is likely to be similarly low. So the pH is more likely to lower naturally (I'll come back to this).
Using pH adjusting chemicals without knowing the KH is very risky. These solutions work by adding acid to the water. But the KH works to keep a stable pH, so it resists the acids. The extent to which it does this is determined by the initial KH and the amount of acid being added. If at some point the buffering capacity of the KH is maxed out, the addition of more acid might send the pH crashing. This latter action can kill fish outright because it is too much too quickly. But the fluctuating pH along the way is also bad as it is highly stressful. At this point, I am going to ask that you read my article which will explain all this better than I can here:
So, we need to know the KH of your source water, and it wouldn't hurt to confirm the GH and pH either. This you can do via the municipal water authority who probably have a website. If you can't fathom their numbers, post the link and we can check.
You can test pH yourself, but when testing tap water always outgass the CO2 or the reading may be false. Shaking the water vigorously for several minutes before testing will achieve this, or letting it stand out 24 hours.
So, back to the pH lowering. If the pH numbers are accurate, I would assume the KH is low so the natural organic processes in the aquarium will lower the pH as the buildup of organics increases the acidity. This is normal and fine, provided it is not sudden and excessive, and depending upon the fish. And at this point, let me say that the fish mentioned will be very healthy in acidic water, except for the guppies, though now days some do seem to manage. But your other fish are soft water fish that occur in acidic waters. I wouldn't mess with pH adjustment. And your GH is ideal for these soft water fish, though again not the best for the guppies. Stay with soft water fish and you will have no problems with water parameters. The parameters for each species is given in our profiles, so you can check them out.
Thank you Byron for your reply, I appreciate you taking the time, and sharing your knowledge.
According to my local water authority:
Alkalinity (as CaCO3): 12mg/L (mean)
Hardness (as CaCO3): 29mg/L (mean) [why are there different values for CaCO3?]
pH 7.7 (mean)
Magnesium: 2.5mg/L (mean)
Total Organic Carbon: 3mg/l [I didn't know if this was relevant or not]
I read a lot yesterday about hardness, so I can't give you specifics or where I remember reading it, but I'm sure that somewhere I read that water with a pH below 6.2 (I think) had the potential to disrupt, or even stop, the nitrifying process. This is what I'm particularly concerned about. I have no desire to 'fight the water' but I would like to bring the pH above 6.0 because it just seems way to low.
Have you heard of this? Do you think that a pH of 6.0 may be damaging to the nitrifying bacteria?
Moreover, I need to ensure that the pH is stabilised at whatever level the water decides to level out to, and it's not stable. After I did a 30% water change yesterday, the pH was reading at 6.2 then this morning it was back to 6.0. You see that, I'm building a case for adding buffer to the water! I'm not sure if that's considered tank-keeping blaspheme or not? I don't wish to be dependant on buffering my tank but at the same time, it needs to be stabilised. What do you think I should do? I have already looked for crushed coral and shells but I'm finding it difficult to source on the internet.
Since the source water has a high pH and I tested my tap water which had a reading 7.4 (this was with water which had been sitting in a container in the laundry for at least 12 hours), wouldn't that suggest that 6.0 is an unstable pH for the tank? And due to some factor in the tank which needs to be remedied or else I'll have a fluctuating pH?
So, I was also reading last night that snails require carbon to build their shell, and plants will take carbon from the water where there is a CO2 deficiency (is this correct?).
Is it possible with the snail outbreak that I had (+the plants with no CO2 input) has depleted what carbonate hardness there was in the water, and that this KH issue might be a temporary problem? What I mean to say is that without the snails, and if I buy some proper substrate like Eco-complete for the plants, maybe the water will naturally return to what it was for so long (pH 7.4) when I set up the tank, because the KH will naturally rise without interference?
Sorry, I've just got lots of questions bottled up! But that's the end of them, thank you for your above response and the post you referred me to, both very helpful.
The GH at 29 mg/l (= 29 ppm, or 1.6 dGH) is very soft (to use a subjective term, but not implying trouble). I'll come back to this too.
One reason is that fish from soft water tend to live in water with GH so low it often can't even be measured, and similarly for KH. The pH can be in the 4's, sometimes even 3's. My tanks may very well have lowered to these levels, I only have test kits down to 5. I leave it alone.
And the reason is that the more you start messing with the source water, the more possible problems there can be. The old adage "select fish suited to your source water" is very good advice. This way, you have nothing to mess with, and the water will be much more stable on its own. There is a great deal to water chemistry, and fiddling with one factor can cause significant reactions.
I have experimented with crushed coral; it is not a good buffer, in fact, one of the worst. It can send the pH soaring, but it does almost nothing to the GH and KH. And as I said, with soft acidic water fish, that are designed by nature through evolution to physically operate best in soft, acidic water, they will be healthier in such water.
Back before 2001 I did use dolomite in the canister filters, about 2-3 tablespoons was all; this does buffer, and it kept the pH around 6.0 to 6.4 in the tanks where I used it. The others stayed below 5. I stopped doing this in 2001 when they started adding ash, and from my tests ever since I have no need for it.
The non-existent GH does cause plant issues, see next.
KH has absolutely no effect whatsoever on fish, plants, snails, etc. It is the GH that matters first, then the pH.
As for enriched substrates like Eco-complete and Flourite, these do nothing, or at most very, very little. I had Flourite in my 70g for two years, and I still had to use Equilibrium and other fertilizers just the same as I do in the other tanks with plain sand or plain fine gravel. The plants were no better, and the GH and pH did nothing, except the pH was a tad higher for a time but this was rather odd as it occurred about 15 months after the tank was setup with the substrate. And it continued after I changed over to sand for a couple months, but has now lowered back to low 6's. Still not sure what occurred here.
Be sure to measure the pH just before lights out.
I think you will find the pH will rise as you add more plants.
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