Carx balancing trouble

Brockly · Feb 1, 2020

Having trouble balancing alkalinity and calcium with carx.

about 6 months ago i swapped from dosing 2 part to using a carx and my calcium and magnesium is off the charts all the time since.

my tank is 100 gallons low to moderate demand mixed reef. I was previously dosing about 100 ml per day of two part to hold My dkh around 7.5 ( I have lower nutrients so need to keep below 8 or I get burned sps tips)

my geo reactor is oversized for tank asni bought bigfor upgrade plans. I does with a kamora pump at 30 ml per minute and hold the reactor at around 7.49 ph to keep my alk pretty steady.

But with this setting my calcium has crept up to 550 and mag is 1500 ish ( I have mag chips in there) must be too much I can take them out mostly . But why is my ca so freaking high?

Brockly · Feb 1, 2020

Also I can’t ever got the tank dkh locked in as people claim with a carx. If I hold at same dose rate With my 7.49 ph my dkh slowly fades over time. If I drop reactor to 7.48 it will slowly climb over time. so I’m right on the edge Of balance but it never just stays. I was under the impression people with carx can just set it and forget it more or less for long periods of time. I have to chase a .01 ph point or it will ultimately just keep swaying

any idea if I’m doing it wrong some how

SeaDweller · Feb 1, 2020

@jda

i hope he chimes in. he explains it better than I can. It is set and forget if you tune it properly. I had to shut mine off cuz my ca is 520, but my alk is also being consumed by a sulfur reactor. If I were you, I’d shut it off, dose alk alone and let ca come down. I’m having to dose alk by hand with baking soda daily until it comes down to 420 again. I love my CaRx though.

Brockly · Feb 1, 2020

Yeah I like it better then mixing 2 part for sure. And tweaking it is as simple as changing 2 numbers in the apex to peg the reactor ph where I want. I thought maybe since I ran rhe reqctor ph at 7.49 instead of the recommended 6.5 or so thst maybe the media was only melting partly and the calcium part is softer hahaha
I’m at a loss I thought it would be easier I guess. Something seems off

Brockly · Feb 1, 2020

For reference. Sorry I can’t seem to get the tanks shot to flip over

Randy Holmes-Farley · Feb 1, 2020

You cannot tune a calcium reactor to adjust the alk to calcium balance, and I don’t really see a way it can be blamed for elevated calcium and magnesium. If you are using it to maintain alkalinity, then either there is an ongoing mechanism depleting alk (like a sulfur denitrator) or there is some other source for the calcium and magnesium, such as the salt mix or excessively high salinity.

jda · Feb 1, 2020

Did you fill the reactor with too much dolomite? Some times you need it but most of the time you do not.

Tune your reactor to run 24/7 and not be interrupted by a pH controller.

Randy Holmes-Farley · Feb 1, 2020

jda said:
Did you fill the reactor with too much dolomite? Some times you need it but most of the time you do not.

Tune your reactor to run 24/7 and not be interrupted by a pH controller.

That would explain elevated magnesium, but would result in lower calcium.

jda · Feb 1, 2020

I have nothing on that...

My tank does not use carbonate and calcium in balance and I mostly attribute that to my large grouping of large clams (does not happen in my tanks without them), but I only need to shore up the levels about ever two or three months and they still are within 85-90%. Nearly nobody has this problem, and those that do usually do not need help if they have grow clams to 8+ inches in captivity.

I have seen some inconsistent results with "barely meting" media... like in the 7s. It is erratic and not really duplicatable. This is why I recommend a tune where the dKh is consistent at about 25 and the media is consistently melting, even if output is very low. I found this more reliable than having dKh or 11 and having a higher flow rate with a presumed higher chamber pH (I don't test CaRx pH anymore). I have also seen some erratic results with extreme "co2 dumping" type of setups where the "controller" cycles on/off too much and dumps too much co2 when it is on - this usually results in a very low tank pH with all of the escaping gas.

Brockly · Feb 1, 2020

Thanks for the feedback so far, so I did put the recommended dose of dolomite in the reactor, but because the reactor is oversized for my tank, that could be how it had gotten so high. I removed it all last night as a way to see if it will slowly come back inline naturally with water changes. The only other filter stuff on my tank is a protein skimmer and 2 of the fat marine pure bricks. Nothing that should be consuming a large part of alk and not calcium along with it. I know a lot of tanks don’t use up both at the same time but this does seem way off, maybe salt. Salinity is 35. I can certainly go to manual dosing alk only until calcium comes down and start again.

So for the set up, (with regards to co2 dumping or whatever you said) since I don’t know a ton about this stuff. My carbon doser is on and running a bubble every 6 seconds or something. And my pump is on 24/7 at a steady drip of 30 ml per second. And then to maintain consistency I use an apex controller to turn on/ turn off the co2 flow when the carx ph is at 7.49.... it does turn on an off about 3 times every hour. And the carx ph bounces between 7.47 and 7.5. So it is pretty steady. But has not “visually melted” at all in 6 months

I have thought about having the reactor ph at 6.2 or whatever for consistent melt. But then my dose rate would have to be much slower like 5ml a minute or so. and I would casually worry about clogging the tube. Might be worth a try though.

The high calcium could be from reef crystals. I just switched to Red Sea blue bucket as I like the levels of it better.

If you guys don’t turn on and off the co2 to maintain a steady ph in the carx, or a steady alk drip (whatever your bench mark). I’m curious what your setup is? How do you control it? Before I used the apex to peg my reactor ph the dkh in tank seamed to always be on the rise or fall. I guess it still is but slowly over 1-2 weeks.

It would be nicer to not have the carbon doser turning on an off multiple times an hour. I could try a slow drip way. Just really need to find a method that is steady. I want to be able to tune it and assume my alk stays the same for 2 months or more. Not 1-2 weeks like it is for me now

Graffiti Spot · Feb 2, 2020

Leave the carbon doser on 24 hours and slow your drip rate down and melt the media at a lower ph. There is no need to turn off the co2 with the setup you have. I had issues when melting media at a high ph like you are as well. With a good pari pump you shouldn’t have to worry about lines clogging.

Shirak · Feb 2, 2020

I am running a similar setup and tuning my CaRx now. I have my Geo main chamber and secondary chamber filled with Reborn with some NeoMag. Masterflex pump is pulling 27ml/min through the system and Carbondoser is set at 10sec/bubble. I also used the Apex programming to hold the reactor at progressively lower pH until the tank Alk was dropping just a hair each day (roughly 7.17pH). I then reduced the Carbondoser secondary pressure so it was running almost steadily at the set pH. I then switched off the Apex control and let the Carbondoser run continuously. At this point tank Alk should be stable or dropping slightly. If it's going up slightly you need to either increase bubble timing or decrease pressure. To tweak the CaRx you then adjust the bubble timing only by very small increments to make the tank Alk stable.

C. Eymann · Feb 2, 2020

Do you do water changes? if so what salt are you using?, other than food are you adding anything into the tank?

Also mag chips are usually made of dolomite which does contain calcium, dolomite is calcium magnesium carbonate.

Most only run dolomite in only a 5-10% ratio to regular calrx media, how much did you add?

Shirak · Feb 2, 2020

I should note there are other ways to tune a CaRx using reactor pH, effluent DKH and volume etc. This is what worked for me because of the pump I am using and tubing size. +1 though on bringing down the reactor pH to start

jda · Feb 2, 2020

I forgot my first advice... check your test kits with another reliable kit. Salifert are cheap and easy to use and good to have around for a double check.

Also, always use a salt with lower calcium levels. You can always add some, but no way to lower it (that I know of). I use IO and add some dowflake (calcium chloride) to it. I also lower the alk with muriatic acid. Trying to find a salt with perfect parameters is a fools errand for me.

Randy Holmes-Farley · Feb 2, 2020

C. Eymann said:
Do you do water changes? if so what salt are you using?, other than food are you adding anything into the tank?

Also mag chips are usually made of dolomite which does contain calcium, dolomite is calcium magnesium carbonate.

Most only run dolomite in only a 5-10% ratio to regular calrx media, how much did you add?

While getting the amount is important, I will reiterate that any amount of dolomite, from zero to 100%, cannot have caused both elevated calcium and magnesium at normal alkalinity.

Brockly · Feb 2, 2020

The mag was probably from the Dolomites chips in too high a quantity. The calcium who knows. Must be my reef crystal salt. I have taken out the mag rocks. I will stop the reactor for now and add just alk part of 2 part solution to hold it while my calcium comes down through uptake and water changes. Once it is back down to an acceptable level. I will restart the carx.

And try a different setup. Instead of a too high, non melt point of the reborn of 7.5 ish reactor ph. I will use like 7 as a start. I will have to lower the dosing flow way down as the effluent will be more potent. But see how this works for awhile. And if I can, try to get my bubble count close enough to the goal reactor ph so so it isn’t turning off and on all the time.

How does that sound? Any other things I am missing?

Shirak · Feb 2, 2020

Sounds good Brockly. You probably won't have to turn the flow down as much as you think to drop the reactor down to 7ish. I would leave all the settings on the CarbonDoser as is and just slow the flow and see where that takes the reactor pH. Once you are in the pH range you want in the reactor chamber you can monitor tank Alk and adjust bubble timing.

Randy Holmes-Farley · Feb 2, 2020

Brockly said:
The mag was probably from the Dolomites chips in too high a quantity. The calcium who knows. Must be my reef crystal salt. I have taken out the mag rocks. I will stop the reactor for now and add just alk part of 2 part solution to hold it while my calcium comes down through uptake and water changes. Once it is back down to an acceptable level. I will restart the carx.

And try a different setup. Instead of a too high, non melt point of the reborn of 7.5 ish reactor ph. I will use like 7 as a start. I will have to lower the dosing flow way down as the effluent will be more potent. But see how this works for awhile. And if I can, try to get my bubble count close enough to the goal reactor ph so so it isn’t turning off and on all the time.

How does that sound? Any other things I am missing?

I don’t think the dolomite is to blame. Magnesium kit error is super common.
Try measuring your new salt water with both kits.

C. Eymann · Feb 4, 2020

Randy Holmes-Farley said:
While getting the amount is important, I will reiterate that any amount of dolomite, from zero to 100%, cannot have caused both elevated calcium and magnesium at normal alkalinity.

@Randy Holmes-Farley

Really? why is that? it has a different composition than calcium carbonate? how can it NOT differ in amounts of cal and mag added in relation to carbonate replenished in the system compared to calcium carbonate alone when used in a reactor?

If I am reading your response right, you are saying I could basically run 50/50 mix of dolomite and reborn in a reactor (or even dolomite only 100%) and not see elevated cal and mag in my system? compared to a reactor running only reborn or even pure calcium carbonate, both tuned to maintain an alkalinity of 8 dkh? because many have experienced, myself included creeping mag/cal levels when using too much dolomite in their reactors.

Im intrigued at you saying that its not possible, can you elaborate why? Im sure there is a advanced chemistry backed reason thats a bit over my head. Can you explain please?

Thanks