Tuning your CalRx | Alternate method thats too easy

ToXIc

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Hey all i've been getting alot of questions concerning my CalRx setup and how I'm running it, and ever since i got TOTM that question had quadrupled lol. So I've decided to make a video about it..

its a little long so please bare with me and i hope it makes your job easier.

 

Randy Holmes-Farley

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I'll just add a few comments...

1. Calcium carbonate will begin to dissolve (melting is an incorrect term here, although I recognize many people use it) at any pH below about pH 7.7. The lower you go, the more dissolves and the faster it dissolves. So it is certainly correct to indicate that you can run a reactor at higher pH than many other people do. The guidelines that folks often give are pH values that work well for them, but higher pH can work. Dissolution should be about twice as fast (e.g., twice as much will dissolve into the same amount of effluent) for each 0.3 pH units that the internal pH is lowered assuming an equilibrium is reached inside the reactor).

2. However, the "efficiency" of the reactor will change as one changes the pH. By efficiency, I mean the efficiency with respect to the amount of CO2 used in relation to the amount of calcium and alkalinity delivered to the aquarium. At higher pH, I think the usage is somewhat less efficient because you will need more water flow to deliver the same amount of calcium and alkalinity, and a certain amount of CO2/pH lowering is needed to bring that water down to the point where any dissolution occurs. The practical impact of this efficiency is probably a lower tank pH if you maintain a higher reactor internal volume pH (for the same delivery of alk and calcium) and a slightly higher expense for CO2. That said, those issues may not actually be a concern for a given tank system.

So, one can certainly regulate a CaCO3/CO2 reactor with a fixed flow rate and a variable pH to maintain tank alkalinity. I might just suggest that if the pH ends up being fairly high in the reactor, the user might consider reducing the water flow through it, and reduce the internal pH a bit, especially if the tank pH seems to run undesirably low.

Happy Reefing. :)
 

ReefCartel

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Hi Just following along and watched the Video. This is the method i use now. The mistake made when I first dialed in my Co2 is the starting point being 6.5 ph and worked my way up instead of starting at a high range and dropped it low.
 

ReefCartel

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"So, one can certainly regulate a CaCO3/CO2 reactor with a fixed flow rate and a variable pH to maintain tank alkalinity. I might just suggest that if the pH ends up being fairly high in the reactor, the user might consider reducing the water flow through it, and reduce the internal pH a bit, especially if the tank pH seems to run undesirably low."

1. Whats considered a fairly high PH in the reactor?

2. If my tank PH is undesirably low. If i reduce the flow to the reactor and lower the Internal PH. Wouldnt that make the PH Inside the Tank even more lower? Or are we reducing the effluent flow?

3. Parameters before I set up my CaCo2, Alk - 6 dkh / Cal - 380

I set up my CaCo2 for the first time on Tuesday. I set my Internal PH to 6.5 - 6.3 as the starting point (10 sec per Bubble). Constant stream with Peri Pump.

Parameters on Wednesday (PERFECT):
(24 hours after set up):
Alk - 8 / Cal - 430

Then Parameters Today (OH NO!):
Alk - 11 / Cal - 450

I want to keep my parameters to the way they were on Wednesday. So I increased the internal PH by setting the Co2 on a timer to turn on at 7.4 and off at 7.0 hopefully this will lower the alk and keep it steady. I will test tomorrow.

My final question for you guys. Should I have done a water change to lower the Alk? or should i wait for it to drop back down after making this PH adjustment??
 

Randy Holmes-Farley

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2. If my tank PH is undesirably low. If i reduce the flow to the reactor and lower the Internal PH. Wouldnt that make the PH Inside the Tank even more lower? Or are we reducing the effluent flow?

I don't think so. It is the total amount of CO2 added to the aquarium that matters if the concern is aquarium pH, not the actual pH of the effluent.

No, don't do a water change to alter that alkalinity. Just reduce the amount of CO2 added (by raising the pH, which you did). Just keep adjusting it (slowly) until you get the alkalinity where you want to be (tune on alkalinity, not calcium, as alkalinity moves a lot faster up and down).

I would say a pH above 7 is probably unnecessarily high inside the reactor, but you can judge that based on the aquarium pH.
 

Diesel

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Does it also depends on consumption by the corals for how much you need?
My Ph in reactor is set off at 7 and on at 7.20.
PH in tank is at the lowest 7.95 at the highest 8.22.
 

Randy Holmes-Farley

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If the tank pH is not too low for your preference, then I wouldn't worry about it. If the air the tank is seeing is not too high in CO2, then the extra input from the reactor may not make an important difference. :)
 

JBNY

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This method works fine if you have a poor needle valve (one that clogs) or not a lot of corals. And probably a good way to start, I think that you end up with a method that as time goes on you have to lower the reactor pH to get more alk (I say alk but I mean alk/ca/mg) from the reactor. I don't see how this is any easier than just setting the pH on the controller to 6.5 and adjust the effluent from there. That way you only have one variable you are working with the effluent rate.

I have been to a few peoples homes and seen their reactor pH set at 7.4 and a stream of effluent going into the sump, and they complain that they are still supplementing their alk/ca with two part, not understanding that the pH in the rector should be lower to get more alk.

My reactor is set at 6.55-6.60 and my tank pH gets to a low of 8 and high of 8.3
 

afamousjohnson

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6.8 on 6.6 off for.me over here. The media also plays a part in finding the sweet spot as well doesnt it? As some work at different ph levels correct?
I am still searching for the sweet spot weekly but blame it on cruddy cal rx equipment
 

ReefCartel

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Originally I set my PH to 6.5 as a starting point and I adjusted my Effluent to the slowest setting but since Im using a Peri Pump it only allows a very slow stream. If i use the needle valve my CaRx will start to leak thru the seams. My Alk jumped from 8 dkh to 10 dkh over night. So im trying this method and raising the PH. I will test again tonight
 

Randy Holmes-Farley

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Originally I set my PH to 6.5 as a starting point and I adjusted my Effluent to the slowest setting but since Im using a Peri Pump it only allows a very slow stream. If i use the needle valve my CaRx will start to leak thru the seams. My Alk jumped from 8 dkh to 10 dkh over night. So im trying this method and raising the PH. I will test again tonight

Raising the pH is a fine way to reduce the release of alk and calcium from the reactor. :)
 

ReefCartel

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34d0e149af3c2c7cad80ccf7bbdbfb46.jpg

PH Seems to be going accordingly. Hopefully Alk drops down a little bit tonight
 

JBNY

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You should turn off the reactor if you want the alk to drop. The point of the reactor is to keep your alk stable. If it is dropping with the reactor running you will need to readjust when you get the alk back down to where you want it.
 

Randy Holmes-Farley

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You should turn off the reactor if you want the alk to drop. The point of the reactor is to keep your alk stable. If it is dropping with the reactor running you will need to readjust when you get the alk back down to where you want it.

Maybe, but since demand drops as the alk drops, a new lower setting will stabilize at some lower aquarium alk level. Whether that stabilized level is where you want it, however, depends on how much you turned it down. :)
 

ReefCartel

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You should turn off the reactor if you want the alk to drop. The point of the reactor is to keep your alk stable. If it is dropping with the reactor running you will need to readjust when you get the alk back down to where you want it.
hmmm your probably right. ill turn it off right now. Turn off the Co2 also right?
 

ReefCartel

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Maybe, but since demand drops as the alk drops, a new lower setting will stabilize at some lower aquarium alk level. Whether that stabilized level is where you want it, however, depends on how much you turned it down. :)

I turned the PH up from 6.5 to 7.4 i checked in 24 hours and the Alk actually went up another 0.3 thats weird?
 

Randy Holmes-Farley

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IMO, when you turn it back on you'll still be guessing how to set it. I personally would only turn it off if the alk was high enough to actually be causing a problem of some sort. :)
 

JBNY

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Maybe, but since demand drops as the alk drops, a new lower setting will stabilize at some lower aquarium alk level. Whether that stabilized level is where you want it, however, depends on how much you turned it down. :)
You could but I've found it tends to not end up where you want it to be so you end up fiddling with it. With me at least, if I turn it off and then back on I can dial it in pretty quickly, the other way can take weeks.
 

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