pH dive, help!

Okay so I set up a stunning Fluval saltwater tank with a heavy light mod, the works. I have 6 pounds of live rock, soft corals and until this morning a very small clown fish.

The clownfish was dead this morning and half the zoos are closed up. This is due to a pH divebomb. Now, is the big question: is it the low gas exchange in the Fluval that may have caused this? Is it true that even if you get the lighting right that Fluvals still can't be a reef tank?

I did a waterchange of about 50% four days ago and I buffered the new water to a pH of 8.2 before adding it as well as heated it to 80 degrees. test once the water change was done and everything was perfect and for a few days everything was happy. then this morning the crash and a ph of about 7.

A friend just gave me a 12 gallon nanocube...I'm thinking of just switching over....but I LOVE my Fluval so much, but if it is going to crash at the slightest touch I think I should just move to 12 gallons.

Check the ph in the evening, it's always low in the morning when lights are off all night, may not be your issue at all, I can't see ph off killing anything and honestly buffering and messing is a hassle, some tanks run normally at a higher or lower ph than others and it varies throughout the day. What do you have for flow in the tank? I don't run covered tanks but I know many do with no issues for years.

I checked the pH again this afternoon and it is still at 7. The zoos are not happy, and it is the only water parameter that I find that is off. I had checked everything two days ago and it was fine, pH 8.2. I'm starting to think that it is a combination of low flow and low gas exchange.

I know the buffering stuff is a pain in the ass, but before I used buffer my zoos were never happy.

Can we get more info on your set up? Just how old is the tank?

Ph buffers do more harm than good. They will raise or lower and bonce back after a day or two. There are only a few safe ways to mess with your PH, ro water, co2 will lower and baking soda should raise it. Baking soda is also what we use to adjust alk which is the buffer for PH. The higher the alk the hard it is to affect your PH, raise or lower.

I use RO water to mix my salt and the pH in the mixed water is always so low.

How much baking soda per gallon do you use?

I don't have to add any to new salt as it is already good I do have to add cal and mg. You should only have to add if your alk is low. I do use it for my 2 part as baking soda is the alk portion and calcium and mag. What brand salt are you using? What is your alk,cal and mag at?