Very low alk with STN - need help!

[Spartan76]

I am having issues with STN. As you’ll see below the likely culprit is disastrously low alk and probably very large alk swings.
Suffice it to say my sps reef had until this point been doing amazingly well now in its second year with weekly water changes of about 15% and kalkwasser fed in by my ATO. I use Reef crystals which in the batch I just tested freshly mixed had an alk of 14. I’ll have to retest it after the water mixes for a day.
When things were going so well over the last few months I got very lazy about testing. My last alk test was 10 dKH about 6 months ago (I had been using a mastertronic but it went out of calibration and other life issues unfortunately took precedence). I am manual testing for now.
Now my alk is very low, presumably due to a boom in sps growth and further frag additions. I did not pick up on this until STN reared its head. Complacency and denial - guilty as charged. I think water changes are probably creating very large swings now that the system alkalinity is so low and the replacement water is so high.
It’s clearly well past time to supplement alk, along Ca and Mg.
I have bulk dry sodium bicarbonate, Ca chloride, and Mg sulfate.

Please help plan a remedy.
System volume is 240 gallons.
I don’t want to do a water change now since the difference in alk between the tank and replacement water is so enormous.
Will try to raise alk 0.5-1 per day using the sodium bicarbonate over the next week or so to target alk=9.
I’ll test ca and Mg along with this and try to keep ca = 500 and Mg to 1300. I understand things correctly , raising the alk that much may cause the calcium to drop. What’s the best approach to restore the alk and keep the Ca and Mg in line?
Should I continue the kalkwasser? Ph peaks around 8.2 drops to 8 overnight. I don’t dose it precisely, have typically added 4 tsp to a gallon and my ato pushes RO water through it.
Other advice??

Current parameters:
pH 8.0-8.2
dKH 2.8
Ca 500
Mg 1250
T 77F
Salinity 1.026
ICP test did not have any trace element abnormalities.

Many thanks in advance!

 

[IPT]

Man, that sucks. I've had similar happen and it all came back to me not being consistent with testing.

Anyway, I am not as versed and many on these forums but I think your plan sounds reasonable. If you trust BRS then they recommend a max of raising Alk at 0.5meq/L or 1.4 dKH per day.

BTW, a DKH of 2.8 seems impossibly low. I assume you re-tested and confirmed using another, different test kit? In the past I have made stuff worse by making knee jerk reactions to sudden changes I detected that were actually either not even present or not as bad as I thought. I always have two different brands of test kits so I can verify if I get a crazy number.

I'm sure others will chime in. Good luck.

 

[DanyL]

Your calcium is this high likely because it’s slightly elevated in kalk rather than being perfectly balanced. 6 months of accumulation could possibly be the reason they shifted this much, but the shift is large enough to doubt results, so I would test with another test kit just to be sure.

As far as going forward - there are 2 approaches.

Some may say that elevating it slowly by .5-1.0 dKH per day is the safer approach and in most cases it is, however - since your corals are already STNing and your Alk is (allegedly) this low - it might actually be wiser to make big and fast shift, elevating your Alk to around 7-8 in one go, which would simulate a transfer of stressed corals from a crashing system into another stable one. The only real problem I see in doing so is the immediate impact on PH, which can be mitigated by elevating the Alk in a separate brute with new water to let the PH settle and only than doing a water change with this high Alk water.

Additionally, and regardless of the system condition I would dip your corals in cipro in attempt to stop the ongoing STN.

 

[VintageReefer]

I would double and triple check the alk manually and boost to 7.0 on day 1

8.0 on day 2

And 8.5 on day 3

And 9 on day 4

There is a calculator online for baking soda dosage to raise alk

Reef Chemistry Calculator

Test ca 12 hours after the alk dosing and adjust as needed. Be on your toes and test frequently and be prepared to adjust as needed.

 

[p1u5h13r4m24]

If you have been doing 15% wc every week how is dkh so low unless you have really good dkh consumption, but my understanding is dkh and calcium are consumed at the same rate, so theoretically u would have low calcium as well.
What are you testing with and are you sure it’s correct?

 

[DanyL]

If you have been doing 15% wc every week how is dkh so low unless you have really good dkh consumption, but my understanding is dkh and calcium are consumed at the same rate, so theoretically u would have low calcium as well.
What are you testing with and are you sure it’s correct?

While the consumption ratio between Alk and Ca are similar to the ratio kalk supplements, they are different - with Ca being slightly elevated in kalk.
So it is technically possible to accumulate it if there were no water changes for a very long time. The difference here is indeed quite significant though, so it could also be a testing error.

 

[Spartan76]

I will retest tonight. I did run the dKh test twice (salifert). I bought another salifert dKH kit, since that seemed the most off, and will retest tonight. I used the BRS calculator and dosed enough bicarb to correct 0.75 dkH last night. We'll see where things land today.
When I do water changes, I observe the pH does boost up to 8.3. I could just do that and then recheck the alk. I'd still have to figure out what my baseline replenishment should be. I'm trying not to shock things but in reality probably have been for some time now.

 

[DanyL]

I will retest tonight. I did run the dKh test twice (salifert). I bought another salifert dKH kit, since that seemed the most off, and will retest tonight. I used the BRS calculator and dosed enough bicarb to correct 0.75 dkH last night. We'll see where things land today.
When I do water changes, I observe the pH does boost up to 8.3. I could just do that and then recheck the alk. I'd still have to figure out what my baseline replenishment should be. I'm trying not to shock things but in reality probably have been for some time now.

0.75dKH in bicarbonate will slightly lower the PH, but it wouldn’t be significant.
The concern about the immediate impact on PH is when dosing a large amount of it all at once.

 

[Spartan76]

Re - tested alk with old kit and new kit same result = 3.3 dkh
Re - tested ca this time got 660-680 (?) twice.
Mg tested >1600. (?) noticed kit is past expiration date
pH = 8.2

So, alk did rise appropriately after adding sodium bicarb.
Not sure what to make of the Ca, Mg results???
Decided to do small (2%) water change to remove some detritus from sump and to see how much this bumps alk (the new water still tested around 15 dkh). Will test again this evening.
STN didn't seem to change much over 24 hrs.
Made no other changes.

 

[p1u5h13r4m24]

This is a wild situation, but given the amount of values that are off I would just try to do water changes to balance everything out. Small daily water changes. 5g a day maybe

 

[Randy Holmes-Farley]

I’d stop magnesium testing. It’s not reliable enough to warrant the effort. It us easy to maintain it without testing.

I’d use the calcium kit in new salt water and see what you get. It may not be giving reliable results.

 

[Luminous74]

As already mentioned, I would be critical in this case and would definitely double-check the measured alkalinity (dKH) with another test or at your local fish store. It wouldn’t be the first time that wrong actions were taken based on incorrect readings.

Also question the measured salinity and make sure it’s really accurate – dKH, calcium (Ca), and magnesium (Mg) are directly related to it.

I would focus on alkalinity first. Alkalinity and calcium influence each other, and at elevated levels, precipitation can occur. But @Randy could probably explain that better than I can.

In your case, I’m not entirely sure what I would do to correct the values. I’d probably go with several small water changes, as a good quality salt will usually push all values in the right direction. That’s assuming your nutrient levels – like nitrate (NO₃) and phosphate (PO₄) – allow for it and no limitation occurs.

I’d aim to get to around 6.5 dKH fairly quickly – within two to three days – as that’s very close to natural seawater conditions. After that, I’d proceed more slowly and cautiously.

Wishing you the best of luck and hope things go smoothly without major losses.

 

[Spartan76]

Before I give an update, I would like to thank everyone who posted thus far for their timely input and help. It is greatly appreciated.
Since the start of this thread I have gradually been able to raise the DKH to 8.0. Calcium is now at 600. Ph 8.15-8.35. My progress was halted for a week midway by an unscheduled emergency work trip, hence the longer than anticipated time to boost the alkalinity.
Fortunately the STN pretty much halted, although for whatever reason today a new colony developed it.
Several of the acropora colonies and even the milka stylos growth tips have gone dormant. I guess this is not a surprise given the recent stress.
I made up a new batch of Reef crystals which I let mix for about a week. The dKH for this batch after a week is now about 8.7. Strangely the calcium tested around 800.
(I bought fresh dKH and calcium test kits.)
The system has 180g sps dense display, 55 refuge filled w Chaeto running on opposite Day/night cycle from the display, 50g sump. I estimate the water volume at 250g.
I’m sending off an icp test including my ro water since I can’t see why my calcium is so high in my replacement water and system.

I am not fully certain how to go forward. Here are my Questions:

1. It seems like my daily alk consumption is around 14g of NaHCO3 (I base this number on the observation over two consecutive days that testing the alkalinity after exactly 24 hours with an additional dose about 14 g did not change the alkalinity). Does this seem a reasonable expectation for a sps dense reef of this size (pic attached taken in happier times shortly before the stn)? I should get more data points but just want to know if this is in the ballpark particularly in formulating a plan for a two part regimen (see #5).
2. At what point should I be concerned about ion imbalances, as so far to correct the dKH, I have added about 400g total of NaHCO3.
3. I held off doing any water changes do to the large difference in dKH between the tank and the replacement reef crystal water. I am now planning to go ahead. I’m wondering if there might be a better alternative to reef crystals? FWIW I have stockpiled 1800 gallons worth of reef crystals, so if possible I’d like to keep using it -but not at the expense of my corals!
4. My top off water runs in through a half gallon reservoir that holds a few teaspoons of kalkwasser. I continue to do that but didn’t refresh the kalk since this episode began. Should I halt the kalk addition? When my calcium eventually falls I would think then to replace w CaCl2 in a balanced manner.
5. I need to move on to a two part regimen. See #4. Planning NaC03, cacl2, mg mix.
6. Any other advice?

Many thanks again!

 

[Randy Holmes-Farley]

I do not have time right now for more than the first question, but 14 g sodium bicarbonate in 240 gallons is about 0.5 dKH. That is not excessive and is a bit on the low side for a typical mixed reef.

 

[Spartan76]

I totally understand: sometimes the demands of life and reefing are not always compatible.

 

[Randy Holmes-Farley]

There’s no reason to not start dosing in a balanced fashion right away. This thread details a fully balanced diy method using sodium bicarbonate, calcium chloride, Balling Part C, and a magnesium additive.

DIY Balling Method Recipe

The Balling DIY supplement recipe utilize a 1:1:1 dosing ratio to maintain proper alkalinity. For instance, if you require 50 mL of the alkalinity solution, you should also add 50 mL of Calcium and Balling. Alkalinity (Choose One) : Option 1: Soda Ash Add 375 g soda ash to enough RO/DI to...

www.reef2reef.com

Reef Crystals is an ok mix. I would not worry about the alk being high. It just acts like a small alk boost.

The kalk is fine to continue. :)

 

[Spartan76]

Thx much appreciate the help!

 

[Val Shebeko]

There’s no reason to not start dosing in a balanced fashion right away. This thread details a fully balanced diy method using sodium bicarbonate, calcium chloride, Balling Part C, and a magnesium additive.

DIY Balling Method Recipe

The Balling DIY supplement recipe utilize a 1:1:1 dosing ratio to maintain proper alkalinity. For instance, if you require 50 mL of the alkalinity solution, you should also add 50 mL of Calcium and Balling. Alkalinity (Choose One) : Option 1: Soda Ash Add 375 g soda ash to enough RO/DI to...

www.reef2reef.com

Reef Crystals is an ok mix. I would not worry about the alk being high. It just acts like a small alk boost.

The kalk is fine to continue. :)

 

[Val Shebeko]

Hello. Need some guidance.

I have just started with Aquaforest 3 part Balling additives. Early days yet but so far Everyone seems to be alive and thriving.

My question is this, my Ph could be higher can I add some diy kalkwasser made up of lye to bolster the Ph without shooting myself in the gills? Do you have a kalkwasser formulation which you prefer?

Thank you and I really your time. Val

 

[Randy Holmes-Farley]

Hello. Need some guidance.

I have just started with Aquaforest 3 part Balling additives. Early days yet but so far Everyone seems to be alive and thriving.

My question is this, my Ph could be higher can I add some diy kalkwasser made up of lye to bolster the Ph without shooting myself in the gills? Do you have a kalkwasser formulation which you prefer?

Thank you and I really your time. Val

Kalkwasser is made of calcium hydroxide. Lye is sodium hydroxide.

What is your pH?