MRC Calc Reactor Setup

[IndyMatt]

I am having trouble dialing this baby in. I was only using 100ml of Randy's Recipe One, using approximately 1.0 DKH of alk per day. Anyway, it get it set to a ml/min and then I come back the next day or even 12 hours later in the day and it is barely dripping. It is killing me! I get a bubble count down and then it would change as well! I finally got the bubble count dialed in about 20 bpm. I checked the Alk of the effluent and it was at 48 DKH. This was not testing error it was truely that high, the only thing I can think of is that with the bubble count and the effluent barely dripping raised the ALK of the reactor effluet do to the Co2 not being release due to such a slow drip rate. When I say slow I mean slow like one drip per 10 seconds. It slowed down to this from a rate of about 10ml/min ! This thing is killing me is there anything that I doing wrong or this just a picky reactor?

[jdieck]

Most reactors can't keep an effluent rate stable below 25 ml/min.
So for an initial setup try setting your effluent flow at 25 to 30 ml/min and then adjust the CO2 bubble rate to whatever needed to maintain 6.8 PH in the effluent.
Test your tank alkalinity and then wait 24 to 48 hours and test again, if the Alkalinity dropped increase the CO2 bubble rate to lower the PH to 6.5, if the alkalinity increase adjust the bubble rate for a PH of 6.9

[KH971]

OK Matt what size reactor do you have MRC1 or or MRC2, what test kit are you using? What reactor media are you using? Answer these three questions and we can start from there.

[IndyMatt]

I am using the C1, using ARM Media, and using the Salifert Alk Kit. It dropped the PH in the tank some and it is a little low right now. I got the AC jr watching over the PH and has the CO2 shut down until the PH gets to 8.25. It is at 8.1 right now. I am also dripping Alk right now to help raise the PH as well. Should I get a PH buffer to raise the PH. I know I slowly raise the PH no matter what I use.

Thanks Guys!

[KH971]

Jdieck pretty much hit it on the head as to where I would start. 30ml a min output. Then leave the bubble count at 20 bpm. Let the reactor run for 24 hours then check the alk of the effluent. 30 ml a min of effluent should be enough to keep your tank taken care of. Do not add any kalk right now and check your alk and cal every night at the same time. Not once in the morning and then the evening. That would give you different readings and you could not compare. If PH of your effluent is 6.8 and your output is 30 ml a min. If your alk and cal drops then you need to bump your output to 40 ml a min and adjust your bubble count to increase it to 6.8 ph output. This all counts if your magnesium count is above 1250. You cannot raise cal if you mag is low. Hope this helps.

[IndyMatt]

When I looked on the Calc. Reactor setup it says that the effluent output should have a DKH of 22 for that value to hold true. When I checked it before the output DKH was around 44 or so. If I increased the output would it lower the effluent DKH?

What should I do about the tank PH? It is at 8.13 right now? Turn the CO2 back on and let the PH stabilize over the next couple of days?

[IndyMatt]

By the way I have been checking the Alk and Calc at about the same time, plus or minus an hour or so.

[jdieck]

What is you tank alkalinity? That is what really counts in setting up the reactor. Your PH can run any where between 8 and 8.1 so do not worry much about it for now.
Also regardless of the effluent PH you should adjust the reactor to keep a constant alkalinity in the tank. Adding buffers PH or alkalinity will make it a lot more difficult to set up the reactor as you would not know if the reactor is really contributing to our alkalinity and how much.
SO lets try it.
Check your tank alkalinity is it between 8 and 10dkH if so then lets start setting up the reactor. If it is less than 8 use some Alkalinity part of the DIY receipe and bring it to aroun 9 for the time being.

There are two variables to play with in the reactor to maintain a constant alkalinity in your aquarium.

Those variables are effluent rate and effluent alkalinity andthe effluent alkalinity is controled by the amount of CO2 added.

There is only three combinations of adjustments you can do:
a) Adjust only the CO2 rate for a given effluent rate
b) Adjust only the effluent rate for a given CO2 rate
c) Adjust the effluent rate and the Co2 rate.

The CO2 rate is what sets and controls the dKh of the effluent. For a fixed effluent (a) above, you can increase the dKh of the effluent by increasing the CO2 and decrease it by decreasing the CO2 so by doing this you can control how much alkalinity is added to your tank. In other terms same effluent at higher dKh more alkalinity into the tank and viceversa.

On the other hand if you keep the CO2 rate constant (b) above and increase the effluent then the effluent dKh will drop so you will not really add much more alkalinity, more effluent with lower dKh, same or less alkalinity added to the tank.

Finally (c) above, more effluent and more CO2 the largest dkH addition is achieved as you have a double contribution, higher effluent rate and higher effluent dKh

The usual method to preven overshooting is to star with a low effluent and low CO2 rate, once you know how your tank reacts to that adjustment you can start increasing the contribution bu sucesive adjustments until your tank alkalinity remains constant over a 24 hour period (between two measurements).

Bacuase every reactor is different and all bubble counters are also different it is difficult to track unless a common denominator is found and that is the effluent PH.
Two different reactors with the same effluent rate and CO2 bubble rate can have different effluent PH and so will have different effluent dKh making comparisons difficult but two reactors with the same effluent rate with the same effluent PH will be adding roughtly the same alkalinity. That is why I always prefer to talk about effluent PH and not about CO2 bubble rate.

The more CO2 rate the lower the effluent PH and the higher the effluent dKh. Now having insured you got this part now you are ready to talk adjustment and it is really easy but reauire patience:

Start with a good initial effluent rate of 30 ml/min and enough CO2 rate so the effluent PH is 6.8 once the reactor has settled into those parameters (It might take a couple of hours of CO2 adjustment to insure it will be at 6.8 est your tank alkalinity. Let the reactor run at those parameters for 24 hours and test the tank alkalinity again. If he alkalinity remained the same you are lucky winner and you are set. If the alkalinity increased just use method (a) above and reduce the CO2 to increase the effluent PH to 6.9 leaving the effluent as is.
If the alkalinity dropped then again use (a) above and increase the CO2 rate to lower the effluent PH to 6.7 leaving the effluent as is. Wait another 24 hours and test again.
If yor alkalinity dropped again then increase the CO2 again to drop effluent PH to 6.6, another 24 hour and repeat if continue dropping but now with effluent PH of 6.5.

For ARM media you do not want to drop the PH below 6.5 to keep it's integrinty and prevent it from crumbling so if in the next round if the alkalinity of the tank is still dropping then use (c) above. Increase the effluent rate to 40 ml/min and also the CO2 rate to counteract the tendency of the effluent PH to increase. Adjust the CO2 to get the same 6.5 you had when you were adding the 30 ml/min but now at 40 ml/min. Continue using (c) above increasing the effluent rate 10 ml/min every time until your tank alkalinity stay constant.

So in short:
Start with a fixed effluentof 30 ml/min and an effluent PH of 6.8, increase the CO2 rate every 24 hours to lower the effluent PH in increments of 0.1 until the alkalinity in the tank is constant or you reach an effluent PH of 6.5
After that if you need to continue increasing the addition increase the effluent rate by 10 ml/min every time keeping the effluent PH at 6.5 by increasing the CO2 bubble rate.

If during the process your tank alkalinity exceed 11 dKh, just shut off the CO2 until it drops and then start the CO2 again but at a lower bubble rate to lower the addition that made it overshoot.

Once your alkalinity is maintained constant, if needed adjust the Alkalinity and Calcium to your targets using the corresponding alkalinity or calcium part of your two part supplement and after that the reactor will keep both at target.

A couple of tips:

a) The effluent dKh level is irrelevant as far as whatever effluent rate and effluent alkalinity you have maintains your tank alkalinity constant. It only becomes important if for whatever reason you need to test for reactor performance or total capacity.

b) Sometimes temperature or pressure changes troughout the day may make the CO2 bubble rate vary a bit (lower and then increase back again) do not worry as far as the overall average is maintained the addition is achieved.

c) Try dirpping the effluent near the suction of the skimmer, that helps to reduce the reactor's PH lowering effect on the tank water.

d) Maintain good aquarium aeration also to help with the tank water PH.

e) Do not worry about the tank water PH unless it drops below 8.0 then just stop the CO2 and sustain your alkalinity by manual supplementation until it is corrected.

f) Never shut off or stop the reactor effluent for long periods of times to prevent fouling of the water inside. If you need to stop the reactor fo ra couple of day just cturn off the solenoid to cut off the CO2 and it will stop adding alkalinity.

g) Enjoy!

[KH971]

Go to Wal Mart and in the cooking section they have a small shot glass sized measuring cup, it has blue lettering on it with ml, this is very helpful in measuring output.

[IndyMatt]

Thanks guys!!!

Well I have been using the wife's tiny measuring cup for measuring the effluent output. It starts at 10ml and goes up by 5ml increments until 50ml.

The tank alkalinity is at 9dkh right now.

I do have one more question, should I set the AC jr to shut the Co2 off if the tank PH goes below 8, such as 7.99? By the way, right now I have the effluent rate set to 30ml/min right now but the CO2 solenoid is shut off by the AC Jr. because I have it set to shut it off if the tank PH is below 8.25. Tonight I will lower the shut off value to 7.99 if that is what you guys suggest.

Matt

[jdieck]

Yes, set it at 7.9

[Billybeau1]

jd, your da man :thumbsup:
:wavehand:

[jdieck]

Hi Billy!...

By the way after reading my long post above again the set up procedure by consecutive adjustments may sound too complicated as described, I think it was long because I repeated the same thing in different ways several times but something I did no mention is that the procedure is designed to insure that the set up is completed at a point where the minimum effluent possible.
Because you can add the same amount of Alkalinity with different combinations of flow and PH in other words you can add the same alkalinity with low effluent and low PH or with high effluent at a higher PH.
IME from those alternatives, the low effluent one (which the procedure above is designed to achieve) not only achieve the goal of maintaining tank alkalinity but it does it so while at the same time retention and contact time in the reactor is maximized.
This increase in conductive to a better utilization of CO2 and conductive to less carryover of unconverted CO2 thus lessening the reactor's impact on tank PH.

[IndyMatt]

I will let you know how it goes. I am following along with you pretty well!

[jdieck]

<a href=showthread.php?s=&postid=9515588#post9515588 target=_blank>Originally posted</a> by IndyMatt
I will let you know how it goes. I am following along with you pretty well!
Good. I am always afraid of confusing people. Let me know how it goes.

[IndyMatt]

I didn't have time to check the ALK of the tank this morning, just ran down and took a look at the AC jr. and PH was 7.94. So the Junior has shut the C02 off. The PH last night right at lights out, 10pm was 8.17. I will check the PH of the effluent when I get home and turn the Co2 down. It is relatively slow now at 20 BPM.

[jdieck]

You might need to improve aeration in the tank. A second reactor chamber might also help.
Try also testing the tank Alkalinity.

[IndyMatt]

I tested the Tank Alkalinity and it was at 8.8 DKH last night (tested at the same time). I made an ingenius routing of waterline to the skimmer input. The problem I had before is that I couldn't rout the effluent to the skimmer input because of where it was located. Now I have a John Guest fitting that I can disconnect check the flow per minute and PH and then hook it into the water fitting that is connected to the water line that is routed to the skimmer input.

After all that I still have my PH dropping! I think the only way around this is if I drip/add Kalk very slowly overnight. I would think that this would be pretty easy if I did this using a peristaltic pump on the AC Jr. What would be a good pump to use?

[KH971]

Alot of people will have their tank ph at 7.9 in the morning and it raises to 8.2 during the day. The second chamber on the reactor will help too.

[IndyMatt]

My Ph this morning was 7.94.

[IndyMatt]

Would it be a good idea to add Kalk at night to help combat the drop in PH? The AC jr. is set to turn the Co2 off if it dips below 7.99. Is a swing of .25 that big of a deal? What is too low as far as PH goes?

[jdieck]

In reality PH starts being a problem below 7.8; adding Kalk at night will help but just need to readjust the reactor output if ncessary not to overshoot the alkalinity.

[ostrow]

Jose: when I get back home I'm going to reexamine my setup to achieve what you say ... I'm not sure right now with the quick setup we have achieved on my system the lowest optimal effluent rate. It may well be balanced in alk addition (someone is coming over to test tonight) but it might be at overall higher effluent rate than needed.

Thanks!

[IndyMatt]

Yeah, I understand that I might need to readjust the effluent rate.

[jdieck]

<a href=showthread.php?s=&postid=9533626#post9533626 target=_blank>Originally posted</a> by ostrow
Jose: when I get back home I'm going to reexamine my setup to achieve what you say ... I'm not sure right now with the quick setup we have achieved on my system the lowest optimal effluent rate. It may well be balanced in alk addition (someone is coming over to test tonight) but it might be at overall higher effluent rate than needed.

Thanks!
You mean you left without adjusting it? Oh My!

j/k :D I do not think we could have adjusted it properly in just 24 hrs so yes you need to go trough the setup process.