Chaeto Controlling pH?

Amoo · Aug 30, 2017

Hey Randy, This is kind of one of those questions I believe I know the answer to, but am going to ask the dumb question anyways because it's driving me batty.

TL;DR version, old sump, new Chaeto, same old mangroves. Tank crash due to extended power outage a few weeks ago, swapped the DT to a 60G, sump is a 75G with a 30G fuge.

The DT is currently mostly barren of life outside of some CUC, 3 fish and a new duncan and small gono. I had to get some new chaeto again from a local reefer (Aipstasia ridden btw thanks bud...) as I had almost complete sump die off. Right now I'm harvesting about a grocery bag size of Chaeto a week. I've never been too worried about pH as it has always seemed to be pretty stable in my tank. What I have noticed recently is that when it's time to harvest my pH is closer to 8.3, and after harvest my pH seems closer to 8.1.

I'm not planning on chasing this regardless of the answer, but out of general curiosity, is it really possible for the Fuge itself to control the pH of a lightly stocked tank?

Randy Holmes-Farley · Aug 31, 2017

Yes, with that much growth and fewer organisms in the display tank, the refugium can dominate the pH cycle!

Amoo · Aug 31, 2017

That's awesome. Now I'm curious at what point I'll hit equilibrium or tank dominant.

Randy Holmes-Farley · Aug 31, 2017

That would be interesting. Keep us updated.

dangros · Oct 4, 2017

@Amoo any update on this?

Bow69 · Oct 13, 2017

Actually a really good question. I am fairly new to this hobby. 1 1/2 years in and my head is spinning from trying to get a grip on all this. I have just experienced the same thing. Trying to run a 90 mixed, heavy sps ATM. I took out half of my chaeto because my fuge was packed and I am trying to get my phospates and Nitrates off 0. Ph has been stable at 3.4 until I remove the chaeto. Dropped like a rock to 8.1. Also ticked up my alk almost a full point. Jeesh, so much to learn.

Rick Krejci · Oct 13, 2017

My reefer 250 is only 1.5 months old, starting with barren reefsaver rock. Dosed with ammonia for the cycle and now have Chaeto with a H380 light. Now stocked with several fish. The rocks are just starting to get a little color, but up until this point my PH was 100% dominated by the Chaeto lighting at night. Now with the tank coming to life, the daytime lights are starting to have an effect as well. Here's my Apex chart for the last several days. The PH rising is 100% correlated with fuge light on the Chaeto. The drop during the day is starting to slow down a little with stuff growing on the rocks.