high alkalinity low calcium and magnesium

[bford]

High Alkalinity and low calcium and magnesium.

Hoping to get some guidance.

Current Tank Status.....
Zero - nitrates, nitrites, ammonia.
Alkalinity = 15 dkH
pH = 8.2
Calcium = 320
Magnesium = 920
Salinity 1.024-1.025
Using Instant Ocean (purple bucket)
90 gallon tank with 15 gallon sump.
Live Rock and Live Sand, no corals.
Had Minimal fish load - blenny, sand sifting goby, yellow tang, pair of clowns, a few hermits and snails, a couple emeralds.

A bit of background....
Had a green hair algae problem a couple months ago (removed fish) - scrubbed live rocks with RODI to clean, removed most of the sand and replaced with new. Dosed Dr. Tim's Waste away to replenish good bacteria. Ran skimmer only for a few hours a day to let bacteria repopulate. Let the tank cycle, then added fish load to get ahead of resurfacing algae issues. Currently Tank has some algae growing but crew is keeping it in check.

Here is where things go sideways.... A few days ago, noticed that dkH was at 14. Fish seemed fine, healthy and were eating. Acting normal. A day or so later the tang and clowns died. Looked like oxygen issues ( to my untrained eye )

Today - everyone else seems to be doing fine. My main question is how do I get the tank back into reasonable parameters.
1) I may have over dosed Waste Away. Would that have an impact on increasing the alkalinity? Decreasing oxygen?
2) I've completed a 20% water change - no impact on Alk, Calcium, Magnesium or pH. Thought this would at least have an immediate noticeable impact.

Any thoughts on how to reverse this situation?

 

[Miami Reef]

What salt mix are you using?

Edit, never mind. I see you are using IO purple.

Have you ever done a test on the new saltwater to see what the alkalinity comes at? At a normal salinity (around 35ppt) you should not be getting those calcium, alkalinity, and magnesium levels.

I use IO and alkalinity comes around 9.5dKH, Calcium around 380ppm, and magnesium around 1350ppm when mixing to 35ppt.

 

[mdb_talon]

Yes waste away can deplete oxygen and without knowing more that would be my best guess for fish death.

As for the alk are you using tap water or rodi? If using tap that could explain your high alk. As for lowering it I would use a low alk salt mix and do 20-30% changes over time to reduce it.

 

[Jekyl]

Removing everything because of some algae was a mistake. Also not a fan of any bottled product for algae removal except phyto. You basically started over at that point. For the testing, what kits are being used? Gotten a second opinion from the LFS?

Algae is a normal thing that all dry rock goes through. Trying to eliminate it with products sets you back imo. I'm not sure what's in those products, but without dosing numbers shouldn't be that high.

 

[bford]

Yes waste away can deplete oxygen and without knowing more that would be my best guess for fish death.

As for the alk are you using tap water or rodi? If using tap that could explain your high alk. As for lowering it I would use a low alk salt mix and do 20-30% changes over time to reduce it.

Thank you for the input. Using RODI. New filters.

Running skimmer full time to reduce bacterial load.

The salt mix I have is lower dkH than what is in the tank. I suspect continual water changes should have an impact over time, but was surprised that the first water change didn't have a proportional impact.

 

[KrisReef]

You need to raise the Mg. The alk/ca/mg balance is best to get Mg in order first (it's a major ion that impacts the others!)

Slowly. I don't recall the recommended increment but getting that in place may just pull the others in a lot closer to what we aim at.

 

[Miami Reef]

I’d stick to 10-20% changes with 3-4 dKH water. PH will be an issue with larger changes. The pH even after aeration of 3 dKH water will be in the 7’s.

@bford You would use sodium bisulfate or muriatic acid to do the above procedure.

Very low demand tanks with no corals can see alkalinity rises with the slow dissolution of calcium carbonate from the sand.

 

[Randy Holmes-Farley]

I suspect the magnesium value is not accurate and would not try to boost the magnesium by so much without more confirmation.

 

[bford]

I suspect the magnesium value is not accurate and would not try to boost the magnesium by so much without more confirmation.

Agree that combination of results seems odd....

Any guidance as to issue with the test? Using Red Sea for both Alkalinity and Calcium. Brand new. Have run the tests a few times a day over the last week and results are consistent. Whether I am consistently wrong or right in how I conducted it is an open question. Although I feel pretty confident that I am doing it right

That being said, I am going to get a new kH test kit as it is older.

 

[bford]

You need to raise the Mg. The alk/ca/mg balance is best to get Mg in order first (it's a major ion that impacts the others!)

Slowly. I don't recall the recommended increment but getting that in place may just pull the others in a lot closer to what we aim at.

Thank you. This was an angle I was considering but not certain it was the right way to go. I am confirming kH with a new test before proceeding.

 

[bford]

Yes waste away can deplete oxygen and without knowing more that would be my best guess for fish death.

As for the alk are you using tap water or rodi? If using tap that could explain your high alk. As for lowering it I would use a low alk salt mix and do 20-30% changes over time to reduce it.

The waste away was dosed prior to adding fish back in and I had stopped a couple weeks before the fish died. Not sure what to make of that. Hoping the skimmer will help set that back into some balance.

 

[bford]

Agree that combination of results seems odd....

Any guidance as to issue with the test? Using Red Sea for both Alkalinity and Calcium. Brand new. Have run the tests a few times a day over the last week and results are consistent. Whether I am consistently wrong or right in how I conducted it is an open question. Although I feel pretty confident that I am doing it right

That being said, I am going to get a new kH test kit as it is older.

I suspect the magnesium value is not accurate and would not try to boost the magnesium by so much without more confirmation.

Update and looking for additional guidance...
Over the last 7 days, I've conducted two 15 gallon water changes. Following the second water change (day 3), I began to see some difference in the water over the last 4 days.

Currently, I am seeing the following:
Magnesium: ranging from 1160 - 1200
Calcium: bouncing back and forth from 380 - 410
Alkalinity: new test kit and confirmed ranges from 17-18 dkH
pH: has remained consistent throughout at 8.2

Questions:
1) Alkalinity seems out of whack compared to other parameters. Any thoughts on why?
2) Since Magnesium is on the low side, what are thoughts on adding? Would that have an impact on helping things get into balance?

 

[Miami Reef]

Alkalinity seems out of whack compared to other parameters. Any thoughts on why?

I very recently wrote this article that may answer your question: The Ways Alkalinity can Accumulate in a Reef Tank

 

[bford]

I very recently wrote this article that may answer your question: The Ways Alkalinity can Accumulate in a Reef Tank

Thank you! I did read the article. A lot of good info. I do believe my tank is accumulating Alkalinity. However, I am having difficulty applying it into my specific situation though. A couple updates....

**Nitrites and Ammonia = 0
**Nitrates = 5 (running skimmer 12 hours during the day)
**Phosphate = 0
**Magnesium has increased and is now in the 1300 range - over the last 24 hours, I've added 3 capfuls of ions aqua vitro magnesium. It seems to have made an impact rather quickly, which I didn't expect.
**Calcium seems to be stable in the low end of the normal range - around 370-400. This has been stable since the water changes and so far unchanged with the addition of magnesium
**Alkalinity is still at 18 dkH
**pH has remained stable throughout at 8.2

Question: Alkalinity has to come down... the question is how best to do that. Option 1: add corals to begin consuming dkH? Option 2: Is a chemical option worthwhile? 30% water change had no impact.

 

[((FORDTECH))]

Thank you! I did read the article. A lot of good info. I do believe my tank is accumulating Alkalinity. However, I am having difficulty applying it into my specific situation though. A couple updates....

**Nitrites and Ammonia = 0
**Nitrates = 5 (running skimmer 12 hours during the day)
**Phosphate = 0
**Magnesium has increased and is now in the 1300 range - over the last 24 hours, I've added 3 capfuls of ions aqua vitro magnesium. It seems to have made an impact rather quickly, which I didn't expect.
**Calcium seems to be stable in the low end of the normal range - around 370-400. This has been stable since the water changes and so far unchanged with the addition of magnesium
**Alkalinity is still at 18 dkH
**pH has remained stable throughout at 8.2

Question: Alkalinity has to come down... the question is how best to do that. Option 1: add corals to begin consuming dkH? Option 2: Is a chemical option worthwhile? 30% water change had no impact.

Have you tested your fresh mixed salt water what does that reading

 

[Miami Reef]

Thank you! I did read the article. A lot of good info. I do believe my tank is accumulating Alkalinity. However, I am having difficulty applying it into my specific situation though. A couple updates....

**Nitrites and Ammonia = 0
**Nitrates = 5 (running skimmer 12 hours during the day)
**Phosphate = 0
**Magnesium has increased and is now in the 1300 range - over the last 24 hours, I've added 3 capfuls of ions aqua vitro magnesium. It seems to have made an impact rather quickly, which I didn't expect.
**Calcium seems to be stable in the low end of the normal range - around 370-400. This has been stable since the water changes and so far unchanged with the addition of magnesium
**Alkalinity is still at 18 dkH
**pH has remained stable throughout at 8.2

Question: Alkalinity has to come down... the question is how best to do that. Option 1: add corals to begin consuming dkH? Option 2: Is a chemical option worthwhile? 30% water change had no impact.

Use muriatic acid or sodium bisulfate to lower the alkalinity to about 3dKH. Change about 10-15% at a time. The pH of the water after aerating will be in the 7’s, so don’t do more than 15% in one shot.

Some folks will add some acid directly into the aquarium, but caution is warranted to ensure it is done VERY slowly and overtime.

The first method above is much safer.

 

[bford]

Have you tested your fresh mixed salt water what does that reading

Have you tested your fresh mixed salt water what does that reading

I am in disbelief..... but two readings on the source water confirm....
18 dkH @ 1.027 gravity (mixed a bit rich to up the salt in main tank which is hovering at 1.024)

Purchased Instant Ocean salt in bulk - sitting in bags. Now that I think about it, I believe it may be the reef mix and not the purple. I believe Reef mix may be 15 dkH?

Tested RODI water and seems to be 2 dkH.

The combo of RODI and Salt mix seems to be the source of the issue.... ugh...

 

[bford]

Use muriatic acid or sodium bisulfate to lower the alkalinity to about 3dKH. Change about 10-15% at a time. The pH of the water after aerating will be in the 7’s, so don’t do more than 15% in one shot.

Some folks will add some acid directly into the aquarium, but caution is warranted to ensure it is done VERY slowly and overtime.

The first method above is much safer.

Thank you sir.... after looking at the source water, would it make sense to add the acid to the water change bucket?

 

[Miami Reef]

Thank you sir.... after looking at the source water, would it make sense to add the acid to the water change bucket?

Yes.

 

[bford]

Use muriatic acid or sodium bisulfate to lower the alkalinity to about 3dKH. Change about 10-15% at a time. The pH of the water after aerating will be in the 7’s, so don’t do more than 15% in one shot.

Some folks will add some acid directly into the aquarium, but caution is warranted to ensure it is done VERY slowly and overtime.

The first method above is much safer.

Wanted to provide an update.... still not out of the woods yet. Had some success lowering pH both in the tank and in the change water.

Suspecting the Instant Ocean salt (purple) was the culprit, I purchased a new bucket. Tested the resulting water and its 16-17 dkH. Salinity is 1.027 in the mixing bucket (still trying to raise in the main tank to 1.026)

Understand IO states alkalinity is 8-12 at 1.024, so I could potentially be higher with a higher salinity?

Will mix the next batch at 1.024 initially to confirm - but wondering if anyone has experienced higher alkalinity than advertised with IO?