I just found this:

Aquariums with a low kH will require more attention to water changes to control the nitrate level reducing the tendency for the pH to drop.

No wonder my Nitrates were doubling every two days - duh!!

All I have to do is get my water hardness up. (as if that's going to be easy)

To bad I cant ship you my water my water is so hard and ph so stable I tried the ph down for a test on a gal of water it took half the bottle to get the ph to move just a point down

Have you looked around for crushed coral hun, that will help keep your ph stable and kh up there.

Well then, you just flipped a light bulb on for me too
I added crushed coral in a media bag to my filter last year but noticed my kH has gone waaaay down again, maybe that's why my nitrates are impossible too! Does crushed coral get exhausted? Should I get a new bag full or just more maybe?

Chrissy

Hmmn, I have crushed shell in the office tank because for some reason the pH would drop only in this tank, I think it must have been something in the substrate which I have change 70%. I use a pH buffer in all my tanks now just to be sure but I might try the crushed shell and see if it makes a difference in the nitrAtes. My nitrates are always crazy and I'm not a heavy feeder.

Is it safe to use shell or coral from the beach if it is boiled first? The bags of crushed shell are huge!

what kind of nitrate readings are you guys getting? My KH is low but my ph always stays the same. I change my water every 3 to 5 days. The highest it has been so far is 10.

I didn't boil mine just rinsed it in a bucket of very hot water out of the tap. Boiling or rinsing well is good because sometimes there are bad bacteria.

Those bags of shell are huge. I use about 2 handfuls for a 30g tank, put it in a mesh bag and put that in the filter. It lasts forever, mine has been there a year and I haven't had to replace it. If there is no room in the filter you can leave the mesh bag on the floor of the tank.