Water hardness climbing ... Need help please.

[Ketso]

This past weekend, I decided to change my substrate from sand to pea gravel from Lowes (hardware store). I like the look sooooo much better but it seems it is causing my gH and kH to climb.

The problem became apparent on Monday, even though I didnt catch it. What happened is that I noticed the pH jump up (I have a DIY Co2 setup running). Seeing the pH jump, I "assumed" one (or more) of my bottles was dying. I counted bubbles and made a new batch in one that seemed a bit off. Yesterday, the pH had risen again and I made a new batch in 2 more bottles and added a new one.

Last night, I ran a full set of tests on the tank (55g) water as the pH wouldnt go down at all and in fact had risen again. This is when I knew that the hardness had jumped wwwaaayyyy up.

I just finished testing my tap water (let it set out all night and day). Usually, it is at 4 dkH, 9 dgH and at a pH of 7.8. Today it measured 3 dkH, 9 dgH and pH of 7.8. Fairly typical.

My tank, on the other hand, has went from the typical 4dkH, 9-11 dgH, and a pH usually around 6.4/6.6 (with co2) to 8 dkH, 19 dgH and pH at 6.8. Last night, it was at 7, 16 and 6.8, respectively.

Could the pea gravel cause the hardness to jump THAT much? I had read on one of the boards, in a discussion over testing rocks, that rocks would only adjust your hardness by a few tenths of a degree so, I am confused on the matter.

Is it the gravel? What can I do to remedy it? Change the gravel again? Any words of wisdom on this will be very helpful.

BTW, No fishies were harmed. None in my tank yet.

[rich311k]

Put some of the gravel in a cup of water and see what effect it has on the KH. Then you will no for sure if it is the cause or not.

[Ketso]

Not sure why I didnt think of that myself, but I didnt. Thanks for the tip rich311k!

[jsoong]

You can dissolve a lot of CaCO3 into your water if it is acidic (& yours is with CO2). You might not see the same magnitude of change if you just test with plain tap (as it is basic at 7.. It all depends on what is in the gravel.

However, you can keep the gravel even if it is increasing your KH. Carbonates will tend to drive your pH towards 8.2 or so, which is not too far from your tap. You will be bringing that pH down with CO2 to the mid 7's (you will need to monitor your KH and your pH for a while to calculate your CO2 level). As long as your fish are not too sensitive (and you don't plan on breeding - some won't breed in hard water), they should be OK with the increased KH.

Once your water is doctored, however, you must remember to keep it stable. you cannot quickely remove the gravel, nor can you do big water changes without matching the KH (10% or so is fine, any more & you will need to add NaHCO3/cc/ etc to your change water). It is reasonable to up the KH in very soft water for buffer capacity & pH stability. I am not sure if all the work (and some risk) is worth it in your case.

[Ketso]

So basically speaking, it would be much less of a headache to swap it out with something a bit more "user friendly". I'll look around. Maybe just go back to the sand. No fish yet, so I have time to swap it.

Thanks very much for the info!

[Ketso]

Well, it is indeed being caused by the gravel. I set up three bowls this morning, all with tap water. One had gravel, one with my shale and the other just water.

Today, when I got home I tested them. The one with just water and the one with shale both were at 4 dkh. The gravel was at 5.

This is very discouraging. Not only do I have a substrate that I like that I cant use, I have, in the short time this substrate has been in the tank, developed tons of diatoms >again<, hair algae, BBA and have some sort of , what I believe to be, algae that is brown and looks like dust balls. Now I will have to trim most of the plants down to nubs again. Remove the gravel. Clean out all the algae in there now. Then replant, etc. Just to go through all this diatom crap again for a third time. I'm nearly 2 months into this and have gotten nowhere. The thought has crossed my mind to just throw out the plants, empty the tank and put it in the garage till yard sale time.

Sorry for venting but I think I should have just gotten some ugly plastic plants and some minnows. No offense to those with plastic plants, it's just my opinion.