Is it time for a CaRx?

[ReeferDog]

3.25 year old system, about 250 gallon total volume. Mixed reef, but SPS/acro dominant.
Been using a kalk stirrer as well as BRS 2-part for Ca and Alk demands. Average Alk reading is 7.21 and Ca is 446 over the last week according to Apex Trident.

My issue is I'm having to constantly adjust dosing volume for kalk, Ca, and Alk to try and maintain stability for those params. I refill my kalk stirrer every week, and the 2-part when it runs out, yet I'm struggling to keep alk between 7-7.5, and my 2 part dosing volumes for Ca and Alk are not 1:1. I'm dosing 200ml of Alk and about 75 of Ca. I'm always bumping up the dosing volume for the kalk stirrer to try and get movement in the params. I understand that the fresh kalk I put in each week will decrease the effluent's potency over time.
I do have a pH monitor that I was using in the stirrer to identify pH drops to determine when I should add more kalk, but eventually I just decided to add 1 cup of kalk every week regardless.

I have Hanna testers for all major params and I calibrate the Trident to those values monthly, so I have faith in the readings I'm seeing.

Is it time for me to go to a CaRx for ease of use? I'm getting tired of constant adjustments to the (3) Versa pumps driving the kalk and 2-part dosing.

 

[USN74NMCB]

Have you checked your Magnisum

 

[Matt L]

Any problems with the coral? A .5 dkh swing isn’t bad. But if you want to change for cost and convenience that’s up to you.

 

[PPBlimpy]

It sounds like it is time.

In the past I would bring my calrx online fairly early and set it to a very low usage, upping my kalk as the tank matured. Then readjusting the Calrx to take more of the load as the corals matured and drop my kalk useage back down and then repeat. I hated always messing with the calrx but adjusting kalk dosing was easy. The readjust happened every 6 months or so as i did it when I needed to swap my C02 tanks. I never waited for them to go empty, always had another on hand and did it every 6 months.

Also would adjust with 2 part when needed. Its a game, do what you can early on to make it easier in the long run.

i have never ran a kalk stirrer, but use a 50G drum for mixed calc.

 

[Randy Holmes-Farley]

The imbalanced dosing seems to be a substantial concern. There’s no rational for such an imbalance in daily demand unless the recipe you are using was not made for 1:1. What exactly are you using?

I doubt your demand in truly imbalanced, but theoretically speaking, if it were, a CaCO3/CO2 reactor wouldn’t be optimal, and if you are constantly need to adjusts doses, that too is not readily done with a reactor.

Can you explain a bit what you mean by having to change doses?

 

[ReeferDog]

Have you checked your Magnisum

Yes, currently 1300, but averages about 1320 over the last week or so

 

[ReeferDog]

The imbalanced dosing seems to be a substantial concern. There’s no rational for such an imbalance in daily demand unless the recipe you are using was not made for 1:1. What exactly are you using?

I doubt your demand in truly imbalanced, but theoretically speaking, if it were, a CaCO3/CO2 reactor wouldn’t be optimal, and if you are constantly need to adjusts doses, that too is not readily done with a reactor.

Can you explain a bit what you mean by having to change doses?

I'm using BRS 2 part, Soda Ash for alkalinity and calcium carbonate for Ca.

I thought that in general, kalk supplemented alk and calcium in equal parts regardless of the potency of the kalk saturated water, which decreases over time. So the only adjustment/change I can make to the kalk stirrer (without topping off with fresh kalk) is to increase/decrease the R/O going into the reactor and then the sump.

If I were to set my Versas to dose 100ml per day of both Alk and Ca, what I see over the next 4-5 days is calcium rising above 450-500 level, and alkalinity struggling to stay around 7.5 dKh. What I end up doing is lowering Ca dosing to say, 75ml/day, and increasing Alk dosing to 125ml/day while trying to add fresh kalk to the stirrer about 1x per week.

 

[ReeferDog]

Any problems with the coral? A .5 dkh swing isn’t bad. But if you want to change for cost and convenience that’s up to you.

Random STN with some of my acros, while others are colored up, have great PE and are growing like crazy.

 

[ReeferDog]

It sounds like it is time.

In the past I would bring my calrx online fairly early and set it to a very low usage, upping my kalk as the tank matured. Then readjusting the Calrx to take more of the load as the corals matured and drop my kalk useage back down and then repeat. I hated always messing with the calrx but adjusting kalk dosing was easy. The readjust happened every 6 months or so as i did it when I needed to swap my C02 tanks. I never waited for them to go empty, always had another on hand and did it every 6 months.

Also would adjust with 2 part when needed. Its a game, do what you can early on to make it easier in the long run.

i have never ran a kalk stirrer, but use a 50G drum for mixed calc.

What do you mean 'and then repeat'? If you were adjusting up the CaRx to take more of the load and backing off on the kalk, what type of adjustment would you make every 6 months when swapping tanks?

Was the 50G drum for mixed Kalk your ATO or was that in addition to your ATO?

 

[Privateye]

I have a dumb question:

Why would we expect 1:1 dosing to be appropriate? I can see it from a coral standpoint, but nitrification depletes carbonate without affecting calcium. So feeding a tank ends up depleting some alkalinity. I've almost always had to dose more alkalinity than calcium. And systems without corals typically have stable calcium and falling alkalinity. Both in fresh and salt water.

Denitrification can restore 50% of the alkalinity lost through nitrification, at least that's what my professors said when I argued for a point on a test. Based on the mass balance, I only got half a point lol.

 

[PPBlimpy]

sorry yes a little confusing.

I would adjust the calrx to take more load off the kalk when I replaced the bottle and refilled media.
6 months was just a good time period and easy to remember. Had the Calrx flow regulated by a dosing head pulling and would up the bubble count of the c02. Then reduce the kalk usage. It was easier to fine tune Kalk by adjusting dose in ml per day then fiddle with the calrx. As the tank matured, corals grew out, more corals added the useage would of course go up.

My 50g was kalk mix used strictly for daily dosing and then an ATO is fed from my mixing station directly on top of that. This system is in place currently on my tank but had a crash back in OCT and slowly getting things back on its feet. pivoting to heavier SPS and LPS if i can get my nutrients back in check.

Since the tank is low load after the crash currently, i am just dosing kalk while I relocate my most my fish gear from the laundry room to the basement.

 

[ReeferDog]

sorry yes a little confusing.

I would adjust the calrx to take more load off the kalk when I replaced the bottle and refilled media.
6 months was just a good time period and easy to remember. Had the Calrx flow regulated by a dosing head pulling and would up the bubble count of the c02. Then reduce the kalk usage. It was easier to fine tune Kalk by adjusting dose in ml per day then fiddle with the calrx. As the tank matured, corals grew out, more corals added the useage would of course go up.

My 50g was kalk mix used strictly for daily dosing and then an ATO is fed from my mixing station directly on top of that. This system is in place currently on my tank but had a crash back in OCT and slowly getting things back on its feet. pivoting to heavier SPS and LPS if i can get my nutrients back in check.

Since the tank is low load after the crash currently, i am just dosing kalk while I relocate my most my fish gear from the laundry room to the basement.

OK, understood, thanks for clarifying. Is it safe to say that people using a CaRx are likely also supplementing Calcium and Alkalinity with other means as well, be it kalk or 2-part?

 

[ReeferDog]

I have a dumb question:

Why would we expect 1:1 dosing to be appropriate? I can see it from a coral standpoint, but nitrification depletes carbonate without affecting calcium. So feeding a tank ends up depleting some alkalinity. I've almost always had to dose more alkalinity than calcium. And systems without corals typically have stable calcium and falling alkalinity. Both in fresh and salt water.

Denitrification can restore 50% of the alkalinity lost through nitrification, at least that's what my professors said when I argued for a point on a test. Based on the mass balance, I only got half a point lol.

I think its a great question. However, Randy would be well more qualified than I to answer that.

 

[PPBlimpy]

OK, understood, thanks for clarifying. Is it safe to say that people using a CaRx are likely also supplementing Calcium and Alkalinity with other means as well, be it kalk or 2-part?

In my experience yes. The calrx will bring ph down slightly. At least my really old single chamber does. I set mine effluent up to go thru my refugium(macro algea chamber) hoping to use up any excess c02.
I have always dosed kalk at the same time to bump ph and be able to fine tune when needed.
I have never used a 2 part but have been looking into it.

Thinking about setting up a dedicated frag system. Just found a 96x24x12 frag tank for a really good deal and have the room to finally set one up! Would probably run 2 part on it and see how it goes.

All of this said I have no idea if I am doing any of it right. Just how I did it 20years ago and how I am doing it now

 

[Randy Holmes-Farley]

I'm using BRS 2 part, Soda Ash for alkalinity and calcium carbonate for Ca.

I thought that in general, kalk supplemented alk and calcium in equal parts regardless of the potency of the kalk saturated water, which decreases over time. So the only adjustment/change I can make to the kalk stirrer (without topping off with fresh kalk) is to increase/decrease the R/O going into the reactor and then the sump.

If I were to set my Versas to dose 100ml per day of both Alk and Ca, what I see over the next 4-5 days is calcium rising above 450-500 level, and alkalinity struggling to stay around 7.5 dKh. What I end up doing is lowering Ca dosing to say, 75ml/day, and increasing Alk dosing to 125ml/day while trying to add fresh kalk to the stirrer about 1x per week.

I agree with the kalk part of the discussion, though it adds excess calcium and may be your culprit. Kalk adds 20 ppm calcium for each 2.8 dKH of alk, but real calcification consumption is only 18-20 ppm calcium per 2.8 dKH because some magnesium replaces calcium in the skeletons and especially in coralline algae.

The unbalanced two part is what concerns me, although if it is only so imbalanced during a correction period to slower calcium, that is fine.

 

[Randy Holmes-Farley]

I'm using BRS 2 part, Soda Ash for alkalinity and calcium carbonate for Ca.

I thought that in general, kalk supplemented alk and calcium in equal parts regardless of the potency of the kalk saturated water, which decreases over time. So the only adjustment/change I can make to the kalk stirrer (without topping off with fresh kalk) is to increase/decrease the R/O going into the reactor and then the sump.

If I were to set my Versas to dose 100ml per day of both Alk and Ca, what I see over the next 4-5 days is calcium rising above 450-500 level, and alkalinity struggling to stay around 7.5 dKh. What I end up doing is lowering Ca dosing to say, 75ml/day, and increasing Alk dosing to 125ml/day while trying to add fresh kalk to the stirrer about 1x per week.

Must be calcium chloride, not carbonate. Are you measuring these out by weight, volume, or just mixing a whole container?

 

[ReeferDog]

Must be calcium chloride, not carbonate. Are you measuring these out by weight, volume, or just mixing a whole container?

I'm mixing an entire BRS Soda Ash 1 gallon mix with 1 gallon of RODI roughly every 3-4 weeks.

 

[Randy Holmes-Farley]

And the calcium mix from BRS is done the same way?

Reason I ask is they also sell sodium bicarbonate, which is half as potent.

Pharma Sodium Bicarbonate 1-Gallon Mix

Ideal for large changes in alkalinity levels or daily dosing in aquariums with high pH. Ultra-pure Sodium Bicarbonate for 2-part dosing in your reef tank! Bulk Reef Supply 2-part additives are the perfect solution to replenish the intake of calcium and alkalinity coral consumes when it grows...

www.bulkreefsupply.com

 

[ReeferDog]

And the calcium mix from BRS is done the same way?

Reason I ask is they also sell sodium bicarbonate, which is half as potent.

Pharma Sodium Bicarbonate 1-Gallon Mix

Ideal for large changes in alkalinity levels or daily dosing in aquariums with high pH. Ultra-pure Sodium Bicarbonate for 2-part dosing in your reef tank! Bulk Reef Supply 2-part additives are the perfect solution to replenish the intake of calcium and alkalinity coral consumes when it grows...

www.bulkreefsupply.com

Sorry, mis-read your prior question. Yes, you are correct the 2 part component from BRS for calcium is calcium chloride that I am mixing the same way. (1) one-gallon mix with a gallon of RODI.

 

[Randy Holmes-Farley]

How long have you been using the 200/75?

It may be correcting for the excess calcium in the kalk.

I used water changes for that purpose when I used kalk.