- Joined
- Apr 14, 2017
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I’m surprised you’re just now noticing this. Whenever I would change my GFO, my alk would drop the first day, to the point where I would increase my alk dosage for three days after changing the GFO. It was super annoying. GFO will bind phosphate or alkalinity.I'm having an issue with my chemistry this week that's really annoying me. I finished out my one gallon jug of BRS HC GFO and started a new one with my reactor change out this week. I've been using 8 Tbsp changed out once a month on our 89g est. system. I've been using it this way since the beginning and never noticed an issue.
This week when I replaced it, I noticed Alk dropped significantly. Luckily I noticed it with my Alkatronic and verified with my Hanna (from 7.5 to 6.88 in 6 hours). I also tested my Phosphate and it had dropped from approx. 0.03 to 0.003. So I think I might have a "new" GFO issue?
I turned off my reactor and tested for a couple days to see where it would go. After 24 hours I was back up to 0.03 and after 48 I was to around 0.06. So today, I turned the reactor back on with only 4 Tbsp of GFO and I'll see what happens. I may have to just wean my system off GFO completely...
It got to the point where I would pre-run my new canister of GFO for a few hours in a bucket before bringing it to my tank. It definitely helped with the alk drop but maybe also was less effective at reducing phosphates.
I’ve read that some people have multiple GFO reactors and alternate changing smaller amounts so there’s less effect on one change.