Tropical Fish Keeping - Aquarium fish care and resources

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denrgb 09-13-2010 08:26 PM

High pH Levels
Hi everyone. I'm a freshwater beginner and I recently purchased a 45 gallon aquarium and set everything up to cycle (without fish). I let it go for about 5 1/2 weeks before finally putting in live plants and a few fish (2 Rainbow Sharks, 2 Angels, 2 Loaches, and a school of 6 Neon tetras). My levels all seemed pretty good. pH 7.0, Ammonia below .25, and low N2 and 3.

I had the tank going what seemed really well for about 3 weeks. I did 25-30% water changes every week, and then all of a sudden a couple of my tetras died. I started testing the water and my pH shot up to 7.6. I tested my tap water and it has always been at 6.8. About a few days later one of my Angels died and then the other. I just did another 25% water change and my pH is still at 7.6. I made the mistake (or what i hear) of throwing in some pH down once a night for two nights. It obviously doesn't work. I've heard about the peat in the filter thing, but I'd rather not have yellow/brown water.

What are some other things I could do to slowly/safely lower the pH and get the aquarium stable again? Also, what would be the cause of the quick rise, and what can I do to not let it happen again?

zof 09-13-2010 08:31 PM

Its going to help to know what kind of substrate you are using along with decorations in the tank. Also test your tap water again but this time let it sit over night before testing it again, sometimes tap will contain Co2 which will lower your pH until it leaves the water.

This is a good starting point but I'm sure others will come along with other ideas.

denrgb 09-14-2010 06:45 AM

I'm using standard aquarium gravel for the time being. I wasn't too comfortable using sand just yet as I'm a beginner. It seems that sand is a little more hard to learn (or so I've been told).

I set some tap water out this morning, and I'll test it tomorrow and see what comes up.

redchigh 09-14-2010 09:46 AM

I would assume that zof is right... Your water will probably be 7.6 after setting out.

The main problem is the fact that your tank isn't cycled. Aquariums won't cycle without something to produce ammonia.
Ammonia and nitrite is probably what killed your fish.
Ammonia and nitrite are also much more toxic when the ph is above 7, but there's not much you can do about your ph....

You could buy an R/O unit for a couple hundred dollars, and mix R/O water iwht your tap to reach your goal ph.
You could buy bottled water/purified water and mix with tap for the desired ph.

Both of these are expensive... Worry about cycling your tank.

What are ammonia and nitrite levels right now?

Byron 09-14-2010 10:34 AM

Agree with previous; let us know the pH of the tap water after 12-24 hours, that will tell us a lot.

And welcome to Tropical Fish Keeping forum.:wave:


redchigh 09-14-2010 02:37 PM

You can also just run an airstone in it for a few hours- that should drive all the CO2 out much faster.

denrgb 09-15-2010 06:05 PM

Thanks for the welcome Byron. New hobby for me and the wife. We're lovin it so far. It seems we're at a different aquarium shop every other day learning this.

The 24 hour tap water has to wait another day (it got dumped by accident). Running an air stone in it now though.

I just tested the water again tonight (haven't done another water change yet) and here is what I have now.

pH: Still 7.6-7.8
High Range pH: 7.8
Ammonia: 0.50 (This shot up for some reason)
NO2: 0.25
NO3: 0.0

I'll let ya know the standing tap water ph test here in a few hours. Thanks for all the help!

denrgb 09-15-2010 09:31 PM

OK I tested the tap water after letting it sit for almost a day and having air pumped into it for about 2-3 hours...

zof was right, the pH of the tap water is 7.6-7.8

What is surprising to me is the 2 rainbow sharks seem to be doing great. After a month, one of them is growing a ton. The wife and I noticed this tonight. The big one hides out in a rock all day and the other swims around the bottom. Otherwise they are always together.

What can I do now to get the pH down again to 7.0 so I can restock the tank with what I lost in the first place?

Thanks again for all the help. This forum is great!

zof 09-15-2010 09:55 PM

Peat, RO/DI unit or a chemical reducer. Depending on your hardness the chemical reducer might or might not work well, but with how much your pH is fluctuating with co2 it may not be that hard so a chemical might work, but its highly recommended not to use such a product because you are adding unnecessary chemicals into your environment.

You also have to remember if your going to lower your pH its going to be much more work when you do water changes and monitoring your water.

Byron 09-16-2010 10:27 AM

Adding any chemical stuff to lower the pH will not work long-term, as I'll explain below. First more critical issue is the cycling.

Letting a tank "run" for 5 weeks or any period without a source of ammonia will not cycle the tank. There is a good article on the initial cycle at the head of this section of the forum, here is a direct link; please read it so you will have a better understanding of the "cycle."

Once you added fish, the cycle began, as that article will detail. With ammonia or nitrite above .25 the best action is a partial water change of half the tank water, using a good conditioner. Once a day will not hurt the fish--in fact, it will save them. Seachem's Prime is a good conditioner to use at this point because it detoxifies nitrite as well as ammonia, and as far as I know is the only one to do both. But the detoxification works for 24 hours, so a daily check is necessary.

Do NOT add any more fish until the tank is cycled; adding a fish means increasing the ammonia, and until the bacteria that handle the ammonia and nitrite are established, this will only throw off the cycle. You will know the tank is cycled when ammonia and nitrite both are zero for consecutive days.

I would also test your source water (tap water) for ammonia and nitrite; some tap water contains one or both, and this is worth knowing so you can be sure you are dealing solely with conditions in the tank. If there is ammonia or nitrite in your tap water, I can explain how to deal with that later.

Now, back to the pH issue. As your tap water test determined, the pH is 7.6-7.8 in your tap water. pH is connected to the hardness of the water. Hardness is the amount of dissolved mineral, mainly calcium and magnesium, in water. The hardness works to buffer the pH, keeping it where it is. When you add chemicals to lower the pH, they do temporarily, then the hardness buffers bring it back. The resulting fluctuations are far more stressful to fish than simply leaving it alone. So, do not use pH adjusters.

As for naturally and safely lowering the pH, this will depend upon the hardness. You could buy a test kit for hardness, but it is easier and less expensive to find out the hardness from your water supply people. Some have a website, or you can just contact them. We need to know the GH and KH if possible; GH is general hardness, KH is carbonate hardness. The KH is what does the buffering, but it is tied to the GH so knowing either will give us a good indication. Once you have the hardness, we can discuss ways of lowering the pH that will not be counter to the hardness. But without knowing the hardness we would just be stabbing in the dark.


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