carbonate build-up issues

[Tom@HaslettMI]

I need some help. I've been having trouble with white build-up on the glass in the refugium for many months (see photo below). It's becoming an issue in the DT. I know it is from the alkalinity portion of the Randy's two part but can't find a dosing strategy that keeps up with demand and doesn't get the white build-up. Here's my current dosing strategy...

• 75mL of alkalinity in the morning
• 150mL of Ca in the evening
• another 75mL of alkalinity before bed

I add the Alk a little at a time over the course of 10 to 20 minutes and all top off water goes through a DIY kalk dispenser. Also, I use baked baking soda for the alkalinity part.

Please help!

[jimsflies]

I'd blame the shark...



Seriously though, I'll have to give this more thought...

What are your calcium and alk concentrations?

[RaysReef]

My best guess, your DIY kalkwasser dispenser could be leaking out kalkwasser into your system.

What do you mean by "Kalk dispenser" using kalk as your ATO with some sort of pump feeding back into your sump on top of adding 150ml of CA and ALK?

[Tom@HaslettMI]

Looks like your DIY kalkwasser dispenser could be leaking out kalkwasser into your system. +1 on alk/dkh and CA test results...I'm betting you have tons of CA precipitation.

The dispenser was added a month ago in an effort to reduce the amount of two part needed... but has not helped. I was under the impression that Ca precipitation happened in the water column. Commonly described as "snowing".

Yeah, I knew you'd ask for water parameters. Getting Ca and alk balanced has been an ongoing battle for me. So, there are definitely times were one is high and the other is low. However, I test alk fairly regularly and normally (and currently) is around 7 DKH. Ca is tested at the LFS (so less often) and is usually in the low to mid range (325-400 ppm). The last LFS test was a over a week ago so I need to get Ca tested again soon (hopefully this weekend).

[RaysReef]

The dispenser was added a month ago in an effort to reduce the amount of two part needed... but has not helped. I was under the impression that Ca precipitation happened in the water column. Commonly described as "snowing".

Yeah, I knew you'd ask for water parameters. Getting Ca and alk balanced has been an ongoing battle for me. So, there are definitely times were one is high and the other is low. However, I test alk fairly regularly and normally (and currently) is around 7 DKH. Ca is tested at the LFS (so less often) and is usually in the low to mid range (325-400 ppm). The last LFS test was a over a week ago so I need to get Ca tested again soon (hopefully this weekend).

Hi Tom, I just wrote a lengthy post to answer your question and got booted out while submitting it and I didn't copy and paste, lol. So I'm trying to retype everything while I'm half asleep now. My sincere apology if I missed anything...

CA precipitation does cause snowing in your water column and so does dumping Kalkwasser into your system and sump.

1st priority- Get a CA/MAG Test Kit *Salifert would be my 1st choice and API next* The API is cheaper and is more readily available at your LFS. (Now this completes your 3 major test kits, since you already have the DKH/ALK)

2nd priority- Decide if your going to dose 2 Part or use Kalkwasser as your ATO *Auto Top Off* as your primary supplement, NOT BOTH. However if the Kalk isn't producing enough CA or MAG in your system then supplement 2 part to balance it out. Also I would dose MAG to stablize your CA and ALK so it won't keep looking like a heartbeat. Just remember dosing MAG will increase your salinity since its a salt-base supplement, so always check after each use.

3rd priority- KEEPing your parameters in check, I would test every other day for the next 2-3 wks and dose or top off accordingly. Once you have a better idea of how much to add then you can go testing on a weekly basis.

Ideal Parameters:

DKH- 8-12, typically around 10 is best
PH- Ideally at least 8.1 (-/+ .1)
Salinity- 1.025 *I hope your using a refractometer*
CA- 380+, I believe anything less than 360 is not being absorbed by your corals
MAG- 1350-1400 is ideal

[RaysReef]

• 75mL of alkalinity in the morning
• 150mL of Ca in the evening
• another 75mL of alkalinity before bed

I add the Alk a little at a time over the course of 10 to 20 minutes and all top off water goes through a DIY kalk dispenser. Also, I use baked baking soda for the alkalinity part.

Please help!

Hi Tom, just did a quick re-read to see if I missed anything...You are dosing way too much ALK. It should only be one or the other...Remember when your increasing your ALK your also changing your PH which can cause alot of stability issues in your system. *You got your baking soda and kalkwasser increasing your PH/ALK thats a double wammy*

Definately I'd just use your Kalk dispenser/ATO as your main supplement for CA/PH/ALK and just use the 2 part after testing your parameters to adjust your levels *CA/ALK/MAG* accordingly. For now I would not add anymore supplement to your system, until you get those test kits to monitor your parameters. If the CA drops don't worry about it too much your corals will be fine, for now get your PH/ALK and MAG in line first. Then we can work with your CA.

[jimsflies]

Kalkwasser adds equal parts of ca and alk. So, yeah in theory it should be enough especially for a smaller system. Is the kalk dispenser the tunze osmolator add-on gizmo? If so, be careful not to pu too much kalk in there so undesolved kalk is not going into the system. The effluent should be clear liquid. Also you want a small air gap were the tube enters the sump to prevent a siphon, but don't have too much as aerating it would cause carbonate to precipitate out.

If you decide to continue the A&B dosing, I would add equal parts of each at the same time to the tank...like within minutes of each other. and be sure to add it at a good mixing point. For example, where your overflow discharges into the sump is normally a good spot.

With kH only in the 7 dkH range, and considering how much your dosing I would agree that the precipiate is likely carbonate. I would expect a much higher dkH. Also what are your magnesium levels? Do you ever add any?

[RaysReef]

Just curious Tom, what is your total water volume including your sump? Also what kind of corals/ livestock do you have?

[ReeferRob]

I was going to add that while I was battling the fluctuating calcium and alk, getting a more stable magnesium reading made it easier to to get the c and a where I needed it to be. But these two dudes seem to have it all covered!

[Tom@HaslettMI]

Thanks all for the helpful insights. First, let me say that this has been an issue for several years and I've tried a variety of things to no avail. So, my responses are not trying to be "Debbie Downer-ish".

Ray,
Thanks taking the time for such a through post (twice even!). I agree with all that you've said. I think getting the test kits needs to be my next step. That way I can get more data, look for trends and try to get this dialed in.

In the past I used just the two part (>2 years) and couldn't keep up with "demand" so I added the kalk in hopes of switching to just that. But after a week of just kalk the levels were crazy low (alk 6 and Ca in the low 300's). So, now I do both and still can't raise the levels. I started with a just little two part and eventually got back to original dosing levels.

As per the second post... I totally agree that I'm dosing too much alk but even with all I'm dosing I can't get the levels where I want them to be or maintain low levels without the current dosing regiment. That's what's so frustrating!

Third post, 50 gallon DT and 20 long refugium/sump. A good mixture of corals. Several large LPS: baseball size favia, >8" diameter turbinaria, large Euphyllia, large caulastrea, Two Tridacna spp. ~8" each, a few SPS: softball size pocillopora, few small montipora spp. (not been doing well lately due to Ca/alk) and a bunch of softies. Check out my Member's Tank thread, the link is in my signature. Wow, after that list I can see why demand might be on the high end.

Jim and Ray,
I do dose Mg and last check (couple of weeks ago) the levels were in the proper range.

Jim,
Thanks for the kalk and ATO advise. The separate dosing was a suggestion by the LFS, as they though that dosing the two parts one-after-the-other may have been causing them to precipitate rather than remain in solution. It has not helped that I can tell.

I agree that this much dosing should be raising the levels but it seems that the alk is building up/precipitation rather than staying in solution. I should also mention that build-up on plumbing, impellers, and bio-balls is also off the charts.

Rob,
I'll get the Mg tested soon. The levels are usually good but it still may be playing a role.