Why would Ph go down?

Byron

Let's find out the KH and GH of your water source before you start breaking up rocks.

Get both if they will, or KH if only one, and get them to tell you the numbers, not "it's normal" or "it's average" or similar, which means nothng.

Don't understand you saying the pH of tap is nothing...must be something.??

Byron.

Calmwaters

I rechecked the tap water and it does come out real close to 7.4 so thats not bad. I don't know why I thought the last time I checked the tap water it did not register anything. I will get the readings you need today when I go on lunch. I would have got it last night for you but I had to work at my second job so I did not have time to go home and then back to the store.

Calmwaters

Ok I got the Gh and Kh numbers. The Gh is 75 and the Kh is around 100.

Byron

These would be ppm (parts per million) numbers, and thus indicate soft water. The comparable dGH would be about 4 for the general hardness of 70ppm; my tap water is 0 or 1 dGH.

That gives us a better idea. The natural biological actions will lower pH by acidifying the water so I don't think there is a problem. The question is, what ph do you want in the tank? I don't see a listing of fish for this aquarium; if they are fish that naturally prefer soft acidic water (tetras, gouramis, rasbora, catfish, loaches...) you might want to let it stay around 6. Adding a small amount of dolomite or crushed coral gravel to the filter would prevent any lowering, and the partial water changes also. I keep my tanks at 6 by this method. It doesn't take much, and I prefer it in the filter where you can add/remove some easily rather than dumping it in with the substrate.

Limestone rock does not work very well for this, as it is slow to dissolve. Dolomite, crushed coral, and I'm told marble chips are all faster and with small amounts. I only have about half a cup of dolomite in my tank filters (115g, 90g and 70g tanks) and it raises the GH by 1-2 dGH.

Byron.

Calmwaters

Thanks Byron. There are Rasboras, Swordtails, Neons, Playts, Cory Cats, Mystery Snails, and female Bettas in this tank. I can not remember the name of the rock I have but I can call the LFS and they can tell me if you think I might should put some into the filter media.

Byron

The platys and swordtails prefer (and do better in) water slightly basic (alkaline), pH in the range of 7.2 to 7.6. The other fish will be happier in slightly acidic water, pH mid-to high 6's. But they can probably adjust to a slightly basic pH if it is done over several days. And using one of the calcareous rock gravels is the safest way in my view.

Dolomite gravel is not expensive, and a very small bag will last years. I would get it, and put maybe two tablespoons in a nylon bag in the filter so the water can flow through it. Monitor the ph and if after 10 days or so it is not high enough add another spoon of dolomite. It doesn't take much, and once it starts to act it will act, so go slow. Gravel is better because the smaller pieces will release calcium more effectively.

The above is if you decide to continue with the same fish in the one tank. To be honest, if it were me, I would not keep livebearers with the other fish simply due to the differing water preferences. Both groups will be better, which means healthier, if they are in their preferred water conditions.

Byron.

Calmwaters

Ok thank you for your help. I will get the Dolomite gravel and see how things go.

MoneyMitch

i wish you the best and dont hesitate to post if you are having complications still after a week or two.

Calmwaters

Thanks Money.