Help! New tank guzzling nutrients

[araziza]

I’m really not sure what’s going on here. I have a 6 month old tank. A decent number of small-ish frags, no big coral colonies or anything. No coralline growing on the glass or pumps, no real purple patches on my rock, just a general purple/greyish hue, no fuge. I’m dosing 800ml/day saturated Kalkwasser. I just spent weeks topping up my calcium, which finally got to 440, then my alk plummeted to 6, finally got it back up. It was 9.2 last night and 8.7today, after the Kalk overnight. I also apparently managed to fall to 385 calcium in 8 days, and despite keeping Magnesium in my ATO, I managed to fall 30 ppm in 17 days, nearly 2ppm a day. How is this even possible on a tank this young with so little coral growth?! And it would be one thing if my corals were growing out of control but I’ve barely seen any growth since the beginning, just a tiny bit! Any help appreciated.

Parameters:
Alk: 8.7(Hanna)
Calcium:385 (salifert)
Magnesium:1305 (salifert)
Phosphate .03ppm (Hanna as of a week ago)
Nitrate (10 as of a week ago, salifert)
Salinity 1.026
Temp 78

Livestock
Torch frag 2 heads
Small hammer coral (2.5-3” diameter)
2” frag Millepora
2 heads Acan
Some small zoa frags
3 blastomussa heads
1 small mushroom
3” gorgonian frag
Bubble tip anemone
Single head Duncan

 

[Tired]

I can't help you on most of this, but IIRC it's not recommended to put trace elements in your ATO. They can settle, meaning you get very little for most of the container, then a ton once it gets near the bottom.

 

[Lavey29]

Are you using RODI to top off in ATO? How do you check salinity?

Weekly water changes? Have you checked your mix?

 

[araziza]

Yes, RODI in tip-off. My salinity is monitored by apex, validated with refractometer.
Thanks for the tip on magnesium.

 

[araziza]

Water changes every 2 weeks. Haven’t checked the mix, but even if it was off, it wouldn’t explain alk dropping .5 dkh over 24 hours after an addition of 800 ml saturated kalk.

 

[Randy Holmes-Farley]

We cannot judge the suitabiity of 800 mL per day of limewater (kalkwasser) without knowing the tank volume, but unless it's a small tank, that's not that much.

 

[araziza]

Sorry, the tank is a Red Sea reefer 200xl, so total system volume ~ 200l/ 53G

 

[Randy Holmes-Farley]

Sorry, the tank is a Red Sea reefer 200xl, so total system volume ~ 200l/ 53G

OK, so 800 mL of saturated limewater (assuming it is saturated, reactors are often below saturation) is adding about 0.5 dKH per day.

That may not be enough to meet the demand. Can you add more each day? If not, you can always use a little two part to boost the alk and calcium as needed.

 

[araziza]

I can. I just upgraded my Kalk container to a 5g bucket, so I can up the dose slowly. At least, I’ll be able to in a couple days, my kessil just crapped out (again, second time in 6 months)

 

[araziza]

I wanted to update this thread, as I've been more baffled by this as time has gone on. I went to the 5g bucket, and continued testing and attempting to up the dosage as I saw alk continue going down. I finally reached 1500mL of saturated (based on quantity added, not from measuring conductivity) per day, at which point I had to stop as it was effectively doing all of my top off water. The alk continued to drop.

As of yesterday afternoon, I installed a Trident on the tank, and although I'd like to see more of a trend over the week, I believe it's starting to confirm that something weird is going on. I dose the kalk starting at midnight in 12 equally spaced dosings. At midnight, right before the first dose, the tank had fallen to 6.17 dKh. I immediately added about 250 mL of reef builder (approximately 3 grams). 6 hours later (after 6 doses, or about 750ml of saturated kalk), the alkalinity was 6.72, almost exactly what it should be if only the reef builder was added, and the calcium had only been rased from 369 to 370 over the whole 12 hour period. I could see the associated rises in PH, but it doesn't look as though the calcium and alkalinity from that kalk ever registered in my tank. And despite the remaining 750mL being added between 6 and noon, my noon test showed 6.71 dKh. Even if the accuracy of the trident is off, I can't imagine the precision is off by so much that it would invalidate all the readings. Even if I wasn't stirring enough, or stirred too much (i stir the kalk with a wooden spoon for 1 minute and then put the lid on the bucket), and the kalk was really weak, you'd assume there would be some miniscule impact at least.

There's no way that my mostly softie, some LPS, all frag tank with relatively sparse overall coral population is consuming enough alk and calcium OVERNIGHT WITH THE LIGHTS OFF to completely negate the effects of 1500mL saturated kalkwasser. What could possibly be happening here?

 

[Dan_P]

I wanted to update this thread, as I've been more baffled by this as time has gone on. I went to the 5g bucket, and continued testing and attempting to up the dosage as I saw alk continue going down. I finally reached 1500mL of saturated (based on quantity added, not from measuring conductivity) per day, at which point I had to stop as it was effectively doing all of my top off water. The alk continued to drop.

As of yesterday afternoon, I installed a Trident on the tank, and although I'd like to see more of a trend over the week, I believe it's starting to confirm that something weird is going on. I dose the kalk starting at midnight in 12 equally spaced dosings. At midnight, right before the first dose, the tank had fallen to 6.17 dKh. I immediately added about 250 mL of reef builder (approximately 3 grams). 6 hours later (after 6 doses, or about 750ml of saturated kalk), the alkalinity was 6.72, almost exactly what it should be if only the reef builder was added, and the calcium had only been rased from 369 to 370 over the whole 12 hour period. I could see the associated rises in PH, but it doesn't look as though the calcium and alkalinity from that kalk ever registered in my tank. And despite the remaining 750mL being added between 6 and noon, my noon test showed 6.71 dKh. Even if the accuracy of the trident is off, I can't imagine the precision is off by so much that it would invalidate all the readings. Even if I wasn't stirring enough, or stirred too much (i stir the kalk with a wooden spoon for 1 minute and then put the lid on the bucket), and the kalk was really weak, you'd assume there would be some miniscule impact at least.

There's no way that my mostly softie, some LPS, all frag tank with relatively sparse overall coral population is consuming enough alk and calcium OVERNIGHT WITH THE LIGHTS OFF to completely negate the effects of 1500mL saturated kalkwasser. What could possibly be happening here?

Precipitation of calcium carbonate might be worth considering as an abiotic mechanism for alkalinity removal. Is your aragonite sand cemented together or free flowing?

 

[araziza]

Ill check when I get home, but I regularly see the pistol shrimp digging and making furrows, the goby taking mouths of sand, and the nassarius and ceriths burying themselves, so I doubt it's all cemented together.

 

[Randy Holmes-Farley]

There's no way that my mostly softie, some LPS, all frag tank with relatively sparse overall coral population is consuming enough alk and calcium OVERNIGHT WITH THE LIGHTS OFF to completely negate the effects of 1500mL saturated kalkwasser. What could possibly be happening here?

Sorry, i didn't see what size the tank is to evaluate the dosing.

A soft coral tank can certainly use 2 dKH per day if there is good coralline growth.

 

[araziza]

Yeah. But so far I have no coralline growth, or at least no purple coralline. There is some green. The tank size is posted above, reefer xl200, so a bit less than 200l (50ish gallon system)

 

[DE FISH]

Is testing error out the question ?

 

[araziza]

Only if both the Hanna and the trident are completely out of whack. The Hanna instructions aren’t exactly complicated and trident doesn’t even require any input from me.

 

[Randy Holmes-Farley]

Only if both the Hanna and the trident are completely out of whack. The Hanna instructions aren’t exactly complicated and trident doesn’t even require any input from me.

Both have issues when the reagents get low.

 

[araziza]

New pack of trident reagent, just started Sunday.

 

[araziza]

I just bought the trident. And anyways, this has been going on for month, with me testing every 3 days or so, and has continued over multiple bottles of Hanna reagent.

 

[araziza]

A couple more days and I think the picture is starting to become clearer. After the 72 hour mark (as per the instructions), I ran the calibration procedure on the Trident. It looked like it calibrated properly, measured the calibration fluid to the exact parameters on the bottle. The first non- calibration measurement taken showed the same rock bottom values (6.25 dKh). I then used some of the remaining calibration solution to check my Hanna. The Hanna read 9.0dKh. Assuming the calibration fluid was accurate to the tag (and I have to assume it was, otherwise I'm gonna go insane), the Hanna is reading exactly 0.7 dKh high. The next morning the Trident shows 6.18dKh (as of 6am). The reading an hour and a half later with the Hanna showed 6.9. That means that if I adjust for the 0.7dKh high readings from the calibration fluid, the Hanna and the Trident are effectively dead in agreement.

I now have 3 possibilities, as far as I can tell:
1) Both testers are wildly malfunctioning. I don't think this is likely, especially after doing the tests above.

2) I have a bad batch of BRS Kalk (or somehow my dosing method with the Kamoer and closed bucket has some issues), AND at the same time I am attempting to compensate using really old batches of seachem kalk and calcium additive, so my attempts to control my elements are failing. I believe this is the most likely option, despite it still seeming a bit of a long shot.

3) My testers are fine, my additives are fine, and there is some other chemistry that is preventing the Kalk or additives from having an impact on the tank, precipitating out or doing something else to not register on tests. This seems like it could be a possibility, but feels like I'm just saying 'I don't know what I don't know'. Eventually I'll probably do an ICP test just to get a clearer picture here.

Since I think 2 is the most likely situation, I decided to try and remedy things from this perspective first. I bought some ESV B-Ionic Calcium and Alk solution, and added some yesterday. It appears to have made an impact on the next test, and the trident read 7.09 on the most recent reading(I have to seriously slow down on my additive, to avoid big swings like this). I'm going to continue to add about 0.5dKh per day until it reads 8 (I assume that will take a few days if I take consumption into account). IF everything works, I'll consider it all a success.