Calcium Reactor - Advice Dialing In

[shaywood]

Last Saturday I added a GEO612 calcium reactor.  The chamber pH is set at 6.5 (using my Apex controller).  I started the effluent drip rate at approx. 50 drips/min.  Each day I have tested the Alk which started out about 7.3.  It has steadily dropped down each day to about 6.5 today.  Yesterday I increased the drips to approx 90/min, but the Alk keeps going down.  This is the same problem I had before I got the reactor.  My pH has been steady at 7.9-8.14.  I tested my Ca once last Sunday and it was at 420.  Does it take a while for the media to start breaking down?

 

[WingRider62]

You might have to drop your reactor Ph a little. As the reactor Ph falls the Alk should go up. Take it slow, like .10 per day and test every day or so.

[albertareef]

Hmm.  This seems odd. If that Reactor Ph is accurate you should be disolving your media at a pretty healthy rate. I would hesitate to push it too far as you can start to turn some media into sludge.  Sorry I can't recall if you already calibrated your electrode or not but might double check that if not.  There was another thread on here recently that had some good advice - one piece of which was that it is often easier to run reactors at higher flow rates then adjust CO2/Ph to hit you target due to the difficulties of maintaining accurate flow at such low volumes. That approach might help you dial it in without risking too low of a Ph in your reaction chamber. 

[shaywood]

Hello.  I was worried about the probe, so the other day I pulled it out and compared the tank reading to my tank ph probe.  They were basically identical.  Also is in line with my calibration solution.

[Bicyclebill]

You need to bump up effluent rate until your alk stays constant. Then adjust alk to desired level with some alk half of two part solution.
What size tank? What type of calcium reactor media?


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[shaywood]

Red Sea Reefer 450 (approx. 92 gallons of water).  Using ARM extra course media with about 10% ZH magnesium.

[shaywood]

Did some more research online, and I think that my effluent flow rate was way too low. At about 90 drips per minute that is only about 9 ml per minute. Everything I read online suggest that I should start out between 30 and 50 ml per minute.

[Myreef]

To raise your alk raise your bulble count and to raise your calcium raise your effluent also might want to look at your mag level too

[shaywood]

Im not sure about raising my bubble count since I use my controller to maintain pH. Do you mean lower the pH. 

[KenH]

Raising bubble count is the same as lowering the pH. I wouldn't recommend going too much lower that 6.5 or you may turn you media into mush.

Since your pH is fixed by your controller, I would suggest increasing your effluent rate a bit at a time while keeping your pH at current level.  Ideally you just want the reactor to reach a balance point where it maintains whatever alk level your tank is currently at, which in this case is 6.5.  

To boost the alkalinity back up to where you want it to be, such as 8 dKH, rather than fiddling with the reactor controls to try to raise it, you should use an Alk supplement like Sodium bicarbonate.  Rule of thumb is not to raise it more than about 1 dKH a day to avoid stress on the coral.

The media starts breaking down immediately once pH gets down around 7 and the speed increases the lower the pH gets.  If you want to know if your media is dissolving and adding any alkalinity to the tank, you can measure the alk of the effluent itself.  It will typically be up around 30+ dKH.  You may need to dilute the sample in order to get it within the measurement range of your test kit such as 50% ro/di and 50% effluent and then x2 the test result.

[shaywood]

Thanks so much.  I did measure the effluent Alk, which was off the scale on my hanna. Something like 300+ (17+dkh).

Ive increased the effluent to 20ml/min and will recheck tonight. 

[Higher Thinking]

To raise your alk raise your bulble count and to raise your calcium raise your effluent also might want to look at your mag level too

I'm just going to politely mention that this is definitely false.

Your calcium and alkalinity levels from the reactor effluent are always going to be going up or down in union with one another. Any adjustments to the reactor will adjust them both.

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