BRS GFO AND ALK

Greenstreet.1 · Jul 5, 2015

I have a quick question. I recently had a bad crash cause of a po4 spike 0.89 so I started using BRS GFO but I find that it is also taking up my ALK also.
The question is. Is there a better GFO that I can use that will not trouble my ALK or is there something I can do to stop it ?

I run GFO in a tlf 150 reactor feed by manifold.

Randy Holmes-Farley · Jul 6, 2015

All GFO has th potential to reduce alkalinity (and calcium, although you notice the alk first) in two ways:

1. Reduced phosphate can increase the skeleton growth of hard corals and coralline algae because phosphate can deter the process. Reducing it can thus make corals grow faster and that increased demand shows up first as an alk decline.

2. The iron in GFO can induce precipitation of calcium carbonate on and just downstream of the GFO. That apparent increase in demand also shows up as increased use of alkalinity.

Greenstreet.1 · Jul 6, 2015

Ok thank you for the info.

Randy Holmes-Farley · Jul 6, 2015

You're welcome.

This has more:

http://reefkeeping.com/issues/2004-11/rhf/index.htm

Happy Reefing.

Greenstreet.1 · Sep 27, 2015

Ok did not wont to create a new thread so will bring this one back since it has to do with alk. I recently dropped my lights down and since then my ALK has been getting used up like crazy (yes I see growth so I know the corals are using it up) I upped my dose to 82ml from 9pm-10am after dosing my ALK is at 7.7 but by the time for my dosing pump to come on my ALK is at 6.7. Any ideas on how I can keep it from dropping so low ?
I was dosing 73ml before the increase.
Sal 1.026
Cal 470
Mag 1440
Po4 0.00
No3 0.10 or under

Randy Holmes-Farley · Sep 27, 2015

You can dose more, or you can split the dosing up over more times of day with the same dose to limit the bottom end of the alkalinity.

Greenstreet.1 · Sep 27, 2015

Thank you once again. Will test later on see where I'm at if its still dropping will go up to 85ml and see what happens

Randy Holmes-Farley · Sep 27, 2015

Do you have the capability to split the dose up?

Greenstreet.1 · Sep 27, 2015

I us an apex to control my brs 1.1ml pump. So I would say yes I do. How do you want me to split it up ? I will try with your help [emoji41] I want to try get alk more stable

Greenstreet.1 · Sep 27, 2015

The dosing calculator I use also give the option to dose every half hr and others.

Randy Holmes-Farley · Sep 27, 2015

I'd split it into several alkalinity additions over a 24 h period. Every 30 min is also fine.

That will make the alkalinity much more stable.

Calcium can do the same, or once a day as it depletes much more slowly on a percentage basis.

Greenstreet.1 · Sep 27, 2015

Hmmm ok so you are saying that my cal also helps keep my alk stable ? If so then I know the other reason why my alk is dropping so fast I have a if hi ph code on my cal and that have been cutting of my cal cause ph has been hi these days.

Randy Holmes-Farley · Sep 27, 2015

Greenstreet.1 said:
Hmmm ok so you are saying that my cal also helps keep my alk stable ? If so then I know the other reason why my alk is dropping so fast I have a if hi ph code on my cal and that have been cutting of my cal cause ph has been hi these days.

No, I'm just saying that on a given day, alk might drop by 20% but calcium would only, in that case, drop by about 3%. So it is desirable to spread out alk dosing, but not really needed (but OK to do) for calcium dosing.