Hi all tested my water today n values are:
Ammonia 0
Nitrite 0
Nitrate 25
GH 4dh
KH 0-3d
PH 7.6
I change 9l in 12"x12"x18" tank every week and add water conditioner and a pinch of bicarbonate of soda.
Two of my fish died quite similarly of swimming erratically, gasping, only passing strings of clear muscus and stopping feeding.
I noticed my KH and GH are low. How do I raise them. My kit suggests calcium carbonate, whats this and how much should I add?
I want to make sure tank is safe and am going to add 1/2 dose of aquarium salt to tank to help condition it.
Any suggestions? Paul

Hi further to myh last post I have noticed numerous little lines like tunnels all over my filter and sythetic plant leaves. Are these just deposits from fish waste or homes for bugs? Small flies have been hatching from my tank for some time.

Your kH is low. Without sufficiant buffer, your pH may not be stable. What reads as 7.6 at one time, may fluxuate greatly over several hours.....

You can raise your kH with baking soda. It will raise your pH, too, but should not be worrisome. There are several types of gH additives you can get - RO right, Goldfish Essentials, uh.........there are others, but I cannot come up with them at this moment.

In all truth, though, I seriously doubt that the water parameters were what killed your fish. Your readings are not all that bad - and pH crashes are very dramatic - you would notice if that is what happened. pH fluxuations can stress a fish, making any other problems that may have been there much worse, though.

If a fish has dramatic symptoms such as yours did, I would strongly suspect a heavy parasite load or a serious bacterial infection or both......

Hi thanks for the reply . I got tetra test strips and they recommend calcium carbonate(chalk?) dolomite stone or marble chips to raise both kh and gh. I don't fancy using baking soda as that will raise ph too high? Do you agree with tetra test sugestions? Also what should i do to make safe my tank from parasites? I only have two ADF's left and don't want to put any chemicals that harm them in. Any advice greatfullt received.
I'm keen to get tank sorted before adding new fish. Paul