Rachel,

I was having consistently low pH for awhile too. I did a test to measure CO2 in the room my tanks were in. Took some water from a bucket of NSW, vigorously aerated it for 10 minutes with an air stone, all the while monitoring pH change with a pH monitor. Did this in the room where the tanks were as well as outside (in January). pH change in the room was very low, about (edit here) .2. pH change outside was something like (edit here) 1.5.

I was astounded at how much CO2 was in our very air-tight condo :eek: After finding out much CO2 and how little O2 we were living with, we decided to open two windows and pretty much kept them open a bit all winter. Now that it is spring, keeping windows open is easy and exchanges the air throughout the whole house, including the tanks.

What is your alkalinity test at? and what do you supplement your reef tank with (calcium, buffers etc)?

If you are talking to me, I supplement with Ca and kalk/baking soda. Am soon getting magnesium to get those levels back up where they should be.

Sorry the question was intended for Rachel.

If you are talking to me, I supplement with Ca and kalk/baking soda. Am soon getting magnesium to get those levels back up where they should be.[/quote]

I dose with kalk about once a week as I don't have a Ca reactor. The point about dissolved O2 in tank is a good one, one of my chem lab experiments this year (a month ago) was to measure the O2 conc. in seawater and I used the water out of the tank, the results were not low. I have had a small cyano algea problem which had almost dissappeared but is starting again. I went and got some carbon to run as well as liquid marine buffer to raise pH as well as some trace elements to try, Still having losses but maybe it will turn around soon. Tommorrow I am doing another h2o change. Will post again with results. thanks for all the suggestions. Rachel

like
Bev says o2 is a big factor too.

I had a big problem until i got some fresh air to thetnak or if the tank is not drilled you will have to get the air into the tank, I found tha worked maybe a air stone then you haveto worry about salt creep too. but that is not a worry .

Did 20% h2o change and measured the pH again. (visual method) and its up to 8 again. mushrooms dying left ,right and center. lost the toad stool as well. Funny enough the sps seem to be doing ok for the most part

Oh no, went browsing by the fish tank tonight and took out more dying mushrooms, one of the hard corals not looking good and then i noticed the FISH ARE BREATHING REALLY FAST. They ate like pigs though, but the sailfin tang is struggling to swim I think. :sad: . I just rechecked all the parameters. the amonia, nitrate and phosphate are no longer zero but not a lot higher, I 'm not surprised due to all the decay going on. the Ca is 450 but the Kh is 12.5!!! Should be 8.WHAT DO I DO????? I think I'm gotting to be sick if I lose everything. Rachel

Sorry to hear about your disaster. Something similar happened to my 180g a few years back. Turns out something toxic died that I did not notice. I ran carbon in my filtration system for 24 hours then threw it out. I also did several 25% water changes, which added up to one heck of a lot of water in a 180g :eek:

Saved less than half of my fish. Corals were untouched. Fish that were affected by the toxin breathed heavily until dead :cry:

I don't think I want to get up in the morning.