Alkalinity and Calcium Imbalance

[ReefRaff]

Hello,


I have been having an issue with my Alk depleting fairly quickly despite regular 3 part dosing. I dose the BRS Alk Calc Mag product and have been a drop in Alk every 3 days despite upping my alk dosage. Below are my parameters and tank info:


240G mixed reef
4 400W Hamilton 20k
4 52W T5
ASM G3 and G4 Skimmer
Biopellet Reactor
3 part Doser
JBJ 1/3hp chiller
2 Ecotech MP60


I dose the following:


80ml BRS Calcium
120ml BRS Alk (recently Upped)
200ml BRS Mag (recently Upped from 0ml the past few months as my Mag has remained 1350. Never the less I thought the lack of mag dosing may be the culprit so I began dosing at apx 1ml/G)
3 Cups of BioPellets
A biopellet booster bacteria added weekly
2 cups high capacity carbon changed monthly
Several drops of lugols weekly


Monthly water change of 50G


Parameters:
Nitrate: Undetectable
Phosphate: .01-.07
Calc: 430
Alk: I supplement to 8.4dkh and it drops to 6.4 within 3 days
Mag: 1350
Ph: 8.3


Im having a tough time trying to figure out why I cant maintain the alk esp with the dosing regiment. I would obviously like to be able to dose calc and alk equally but for some reason I cant.


I read an article by Randy Holmes that stated, "There are some other processes that can lead to alkalinity depletion, including partial cycling of nitrogen (from organic compounds to nitrate and no further).."


Could this be the cause as I do use biopellets? Any suggestions would be greatly appreciated.

 

[Built347]

I cant really answer your questions but I bet your having some issues with sps at 6.4. If I get below 8 acros start getting *****. Dont know much about bio pellets.. I thought I heard bp will pull alk down.. maybe it was bp works best at low alk.. idk.. never used em.

Sent from my SGH-T889 using Tapatalk 2

 

[Nuocmam]

I would verify your test kits with somebody else's.

 

[ZoaCollector]

Get a calcium reactor it saves you money and trouble


Sent Via the R2R Forum APP

 

[Singlefin]

Double check your test kits. I thought my mag was always low. Kept adding and adding. Turns out my kit was bad. It was over 1500. This threw off my calcium and alk numbers. I think I dose 100ml of calcium a day on my 40b. How stocked is your tank?

 

[Downbeach]

The uptake of Ca and Alk, by “stony†type coral, coralline algae, etc. in a reef system is 20 ppm Ca to 50 ppm(2.8dKH) Alk(CaCO3), which is a ratio of 2 pts Ca to 5 pts Alk (2:5). Equal doses of any two part supplements are designed to provide the same ratio's. So, they will all work but, I have found that the brand name products are going to be more expensive. I use one of the BRS recipes. You're not mixing the recipe's are you, i.e. Ca from recipe 2, and Alk from recipe 1?

Saturated kalkwasser also contains this same ratio, @ ~ 800 ppm Ca(2pts.) to 2,000 ppm CaCO3(5pts.). It also has the added benefit of utilizing some of the CO2 in your system, which may help keep your pH in line. Even though I'm using a two part recipe, I also still use the kalk in my dosing regimen. The problem with kalk is that it’s limited in its ability to keep up with a high demand due to the fact that you’re limited to how much you can add to RO/DI water(2tsp.), and your evaporation rate. You can boost that to 3 tsp. with the addition of vinegar, but that also adds a carbon source, and potentially other issues.

If you're using a "reef" grade of salt mix, i.e. Reef Crystals, I'd make sure the salinity is right, by measuring it using a calibrated (@35ppt) refractometer, or metering device. This will ensure you are adding enough Ca, Alk and Mg when you do your WC's. With normal WC's mixed to a salinity of 1.026, I've never had to add Mg, using this type of salt mix.

Except for the fact that I have a slightly smaller system (180), and use LED's, our systems are similar. How do you have your dosing set up? What salt mix are you using? What's your SG, and what are you using to measure it with? Is your WC done once a month or is the 50 gal. done throughout the month?

Here's a good article, if you haven't seen it already:

Chemistry And The Aquarium: Solving Calcium And Alkalinity Problems ? Advanced Aquarist | Aquarist Magazine and Blog

There's a couple others I would add, but Reefkeeping's server has been down for a day or two.

 

[beaslbob]

use the diy two part system. Where you dose calcium and alk when alk drops down.


my .02

 

[mcarroll]

Sounds like you are not dosing continuously even thou you have dosers? Am I misreading?

If your dosers run continuously, and you aren't seeing pH drift at all with your buffer levels (6.4 makes pretty big swings possible, but not guaranteed) and Mg numbers aren't coming up in spite of dosig, I have to say you are precipitating Mg with the alkalinity somewhere.

1350 ppm Mg is nearly perfect anyway, so maybe cut back on Mg to what it was before the problem started and see if your alk stops "disappearing". (the normal difference in alk consumption from the coral ratio is minor, not major...you can notice it in testing, but doesn't take much to correct for it.)

Any chance you don't need such an aggressive biopellet and carbon routine?

BTW, what's your population of stony corals like? Possible to post a tank shot?

-Matt

 

[Reefing Madness]

Start dosing everyday. Its obvious your tank is eating it quite quickly and needs it, or you wouldn't have to dose.