PH swing from .22 to 0.00 in 12 hours

[Matt Winstead]

So got home last night and tested Phosphate and alkalinity on my 250g LPS tank. Phosphate was .22 I had some new corals and feeding more reef roids than usual. Also my alkalinity was 7.5 and I like it more than 8 so I dosed 6tsp soda ash. This morning alk was 9 great. Since my Phosphate was .2 and I want 0.5 or so I filled my two canister reactor with about 2/3 carbon and 1/3 GFO. This morning the phosphate is 0.00. How can it swing so fast so much just from a little GFO on a 250g tank? Everything had remained the same

 

[chipmunkofdoom2]

Since my Phosphate was .2 and I want 0.5 or so I filled my two canister reactor with about 2/3 carbon and 1/3 GFO.

Assuming you meant your phosphate was 0.2 ppm (200 ppb) and you want it to be 0.05 ppm (50 ppb)?

Whatever the case, assuming you double checked your test results, it's totally possible for GFO to strip phosphate that quickly. If you installed 1/3 GFO in two canisters, you basically installed a total of one canister filled 2/3 the way with GFO. If you're using standard 10" RO filter housings for your canisters, that's a significant amount, even for a large tank. You should consider taking some or all of it offline. Going to zero phosphate that quickly has caused problems for reefers.

 

[Matt Winstead]

Thanks for the advice I just turned my Reactor pump off!