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Optionman
10/18/2016, 08:18 AM
I recently added a 5.5 inch dual chamber reef octopus calcium reactor to my Red Sea S650 (175 gallon total) reef controlled via an Apex Fusion ph probe. The 1st chamber contains CaribSea ARM media and the other has magnesium media. My tank is 6 months old and prior to adding the reactor i was 2 part dosing at 1ml/gal/day (175ml/day or approx 20ppm of calcium). Even with the 2 part dosing, but before adding the reactor, my calcium level ranged between 380-400. i do 15% water changes approx every 10 days and the tank is very well stocked.

The reactor has been running for 3 weeks and i have continued to 2 part dose at the prior level (1ml/gal/day) and yet my calcium still ranges from 380-400.

The Apex is currently set to turn on the CO2 when the ph within the reactor reaches 6.6 and turns off when the ph hits 6.4. based on my current drip rate this produces about a 90 minute cycle (CO2 on 30 min and off 60 minutes).

From what I've read the CaribSea ARM media melts best at a ph of 6.5.

What can i do to increase alk/ca output?
What does increasing the CO2 bubble rate do other than speed up the rate at which the ph within the reactor drops?
Should i be aiming for a CO2 on/off cycle that's longer or shorter? i've read posts that say that CO2 should bubble into the reactor constantly and others that say that the effluent drip rate should be high as possible.

I'd appreciate any feedback, especially from anyone using an Apex Fusion ph probe to control a calcium reactor.

Thanks in advance.

BlackTip
10/18/2016, 08:27 AM
Having Apex turn on/off the reactor is a bad idea. Reactor should be running 24 hours. What you need to do is to tune your reactor and leave it running continuously. Apex should only intervene by shutting off the reactor in extreme circumstances like PH too low and leaks.

There are plenty of detailed literature on the web on how to start and tune a calcium reactor, so I am not going to do a better job explaining it here.

Optionman
10/18/2016, 08:39 AM
Just so i understand your comment, you're saying that CO2 should be bubbling into the reactor 24/7 ? (just use the Apex for emergency shutoff)

I'm assuming that i then adjust the drip rate to keep the reactor's internal ph stable around the desired 6.5 level.

I will look for the literature, thanks.

scar79
10/18/2016, 08:54 AM
The Apex will be the best way to accurately and reliably control the pH in your reactor and you should continue to use it to do so. That said, I would decrease your bubble rate to the point where it drives down pH in the reactor very slowly, but still drives it down. You might also consider closing up your hysteris so the off-time is shorter. This way, you CO2 might be on for 5 hours and off for 15 minutes, thus delivering a steadier pH. While this won't have much of a difference on how your reactor is currently operating, it does provide you with a safety factor if your reactor's pH probe or solenoid were to fail on.

As you increase your effluent drip rate, your reactor's pH will climb faster as tank water cycles through it at a faster rate.

As BlackTip noted, there are a few articles on properly tuning your reactor. Also, I think what he's referring to with Apex control is in regards to supply/effluent flow. Your reactor's feed should only be shut off in the event of a leak, or if your tank pH drops too low (suggesting a failure of your reactor pH probe and a continuing supply of CO2 to the reactor), in which case shutting off the feed is the only immediate way to stop the pH drop.


Definitely an interesting topic and I'd love to hear more practical feedback from others. My CaRx is sitting empty in a closet right now until my new tank grows up to the point where 2 part starts becoming cost prohibitive.

BlackTip
10/18/2016, 09:14 AM
Just so i understand your comment, you're saying that CO2 should be bubbling into the reactor 24/7 ? (just use the Apex for emergency shutoff)

I'm assuming that i then adjust the drip rate to keep the reactor's internal ph stable around the desired 6.5 level.

I will look for the literature, thanks.

Yes, that is correct. You want the reactor internal PH stable. Internal PH doesn't have to be 6.5. The alkalinity production is a function of effluent rate and effluent alkalinity level. So, for example, someone could be run 25ml at 6.2, and another could run 50ml at 6.6, and both could produce the same result. The type of media you are using play a role as well. Some media dissolves below 7.0, and other media requires 6.5 and lower.

This is a good article, and there are many more online and videos as well.
http://www.reefkeeping.com/issues/2002-05/sh/feature/

bertoni
10/18/2016, 07:08 PM
I agree with tuning the reactor so that the carbon dioxide is flowing continuously. You could use the pH meter as an emergency shutoff, if you'd like.

Optionman
10/20/2016, 08:22 AM
Thanks for all the recommendations. I played with the bubble and drip rates and have now established a slow but continuous bubble rate and strong drip rate, both while maintaining a level internal PH of 6.5

I will let this run for 48 hours and test effluent alk/ca.

Thanks again for all the responses.

bertoni
10/20/2016, 06:26 PM
Okay, please let us know how well it works for you!

aznxgqb0yx
10/20/2016, 09:21 PM
https://youtu.be/gwlvfgDvQqg

Optionman
10/25/2016, 08:11 AM
UPDATE:

After adjusting the reactor as discussed in above post, i am dripping 70ml/minute with an effluent ALK measured at 28-30. My tank's CA/ALK are holding steady at 400 and 13.7 (5mL) (using new seifert test). My tank's PH is 8-8.2

i very much appreciate all the feedback on this topic and will update as necessary.

BlackTip
10/25/2016, 11:58 AM
:thumbsup:

bertoni
10/25/2016, 06:53 PM
Okay, those numbers are acceptable, although I'd probably let alkalinity drop a bit to 11 dKH or lower.

Wiskey
10/25/2016, 07:50 PM
I agree. I would turn back the reactor drip rate and use some CA 2 part to keep the CA at around 420 while the alk falls. I prefer around 8 or 9 DKH.

Whiskey

Optionman
10/26/2016, 07:23 AM
Appreciate the feedback. I'm using Red Sea Coral Pro salt mixed to 35ppm and it's ALK is listed at 12.5-12.7. i was concerned my ALK might be a little high and will continue to monitor and adjust reactor as necessary. Coral growth looks good and i will see about dosing just a little CA to raise to 420-440 area.

hkgar
10/26/2016, 02:32 PM
Dose your CA to the desired level and the reactor should keep it there.

Something does seem strange though and that is your Alk usage. At a flow rate of 70 ml/min and an effluent Alk of 18 your usage rate of Alk is 3 dKH /day. I have a heavy SPS 180 tank and use .8 dKH /day. Maybe you mean 70drops per minute?

http://reef.diesyst.com/reactor/reactor.html

Optionman
11/04/2016, 08:31 AM
UPDATE:

for the past week the reactor has been dripping at approx 55ml/min (ml, not drops) with an effluent alk of 30dKH.

My Magnesium is 1480
PH 8
CA holding steady at 390-400
Alk 14, as high as 15 in one test

My tank seems to be doing great, ridiculous growth in xenia/kenya tree and birds nest, and all my sps corals are encrusting on rocks and look healthy. My tank is well stocked, including a very large colt coral and a large finger leather coral.

I have yet to add any CA only in an attempt to get the CA up to 420-440, but will most likely do so this weekend.

I use Red Sea Coral Pro salt which mixes to an alk of 12.5 so i'm not too concerned about my Alk level, but still this level seems at odds with all the posts i see on this forum.

Appreciate any further feedback.

BlackTip
11/04/2016, 09:31 AM
Some people reported bad side effects running alkalinity that high. You may want to google the topic and see whether it applies to your tank.

bertoni
11/04/2016, 08:54 PM
Okay, the tank seems to be doing well, so I wouldn't worry too much, although I agree that the alkalinity is rather high.