High kH after sitting fallow

[jasonrusso]

So my 210 gallon FOWLER tank has been empty since April 22. I've been leaving it fallow for 76 days to eradicate a velvet outbreak and figured I would kill any crypt or fluke issue as well. I haven't really been doing anything to the DT except for feeding the crabs and biofilter a couple times a week. I also keep my ATO full. I removed the filter socks for the time being as there really isn't anything to filter out.

My fish are due to be reintroduced this weekend so I checked the water parameters today. The results are as followed:

pH: 8.2 (confirmed by my apex)
Ammonia: 0
Nitrites: 0
Nitrates: ~5
SG : 1.023
kH: 16??

The kH is what has me confused. When the fish were in there, I used to add a buffer to the water to try to keep the kH over 8. I have done no water changes since the tank has gone fallow and I do not dose any trace elements.

I did try to treat the tank with Chloroquine Phosphate before I removed the fish to QT. I added my carbon back in to the tank to remove the medication due to excessive die off (that I did not expect) from the CP.

Do I need to be concerned about the kH? Will this affect my fish in any way? How do I bring it down to a more reasonable level of 12dkh?

 

[Scott.h]

I wonder if something is leaching from rocks. Is it possible the test kit is bad? You could drip hydrocloic acid to a high flow area of the sump to reduce alk, but it will drastically (temporarily) kill ph. I've only done that to empty tanks or my regular new sw water change water. If there are living things in the tank go really really slow and it would be fine.

 

[jasonrusso]

I thought about A bad kit but I confirmed it with another test kit (API and Red Sea). I really don't mind if it will not affect my fish

 

[jasonrusso]

Oh, and I don't have a source for HCl.

 

[Randy Holmes-Farley Verified Community Expert]

When you say feeding the biofilter, what does that mean?

If nitrate was very high and came down, that will raise alkalinity.

 

[jasonrusso]

Feeding the biofilter meas throwing some pellets in 2 times a week. This is for the crabs and snails as well.

 

[jasonrusso]

When you say feeding the biofilter, what does that mean?

If nitrate was very high and came down, that will raise alkalinity.

Yes, the nitrates were high after the ammonia spike from the CP. That would explain.

Does this affect the fish at all? The nitrates were lowered with biopelllets, PO4/NO3 reducer, and an algae reactor

 

[jasonrusso]

When the nitrates got low I stopped dosing the PO4/NO3 solution

 

[Randy Holmes-Farley Verified Community Expert]

I expect the fish do not have any issues with that alkalinity.

 

[Scott.h]

You could dose muratic acid as well, available at any large hardware store. A little goes a long ways. But if you have a lot of invertebrates those are sensitive to alkalinity and sudden swings in pH and such.

 

[brandon429]

this thread has strong hidden details

Im reading the subtle claim here so far is test error, that no mechanism exists to drive up alk any different than if fish have been in the tank

I will spend all day wondering here what would spike alk given only removal of fish and literally no other changes. seems test error is the only explanation so far. not that it isn't being ran correctly to the other times, but some variation has come up?

 

[brandon429]

I know from prior readings that Randy mentions CO2 and alk aren't tied in the way high co2 drives down alk

fish impart co2 and consumption of oxygen as a couple effects on a system

they also command more feed

so, as a possible mechanism brainstorm in case the alk is verified spiked for sure in the absence of fish, what if much less feeding is much less protein digestion in the system, and those acids (metabolic byproducts) do lower the alk when the system runs normal, so lack of same-amnt degrading proteins in the system is less uric acid less X acids etc

how else can fish modulate alkalinity Randy= fun thread. so Co2/carbonic acid wont affect kh, what about other acids associated with fish loading which should convey the same actions as muriatic lowering of alk


*one could also make the case less fish/less systemic bacteria and bacteria can use carbonate up in their actions...that goes against what we've typed up in the ghost feeding is a myth thread, but again I can see someone coming from that angle soon enough as a possible explanation (by taking out fish, the filtration bac downscale to meet new feed shortages, and use less alk from the system)

 

[jasonrusso]

this thread has strong hidden details

Im reading the subtle claim here so far is test error, that no mechanism exists to drive up alk any different than if fish have been in the tank

I will spend all day wondering here what would spike alk given only removal of fish and literally no other changes. seems test error is the only explanation so far. not that it isn't being ran correctly to the other times, but some variation has come up?

What are the only ways that the kH can go up. I did not know that high nitrates could cause this.

I also did not add any buffer.

I also questioned the test, that's why I did it again with another test kit and I got the same result.

 

[jasonrusso]

If I was Muriatic acid was to be used, what dosage would I use.

 

[brandon429]

I wouldn't mess with it yet till Randy has a chance to chime in. Im poor chemist, what Im distilling out of this thread is conflicting questions I had from many older threads on alk and ph from reefcentral. highly curious as to what he reco's here

*I don't like to advise responding to alk changes we haven't pinpointed. In the nano reef realm, we usually just do huge water changes to balance things out/safer

 

[Randy Holmes-Farley Verified Community Expert]

I wouldn't add muriatic acid if there's anything living in it. The pH will bottom out. Temporary, but very low. IMO, that's just a plan for new salt water alk lowering.

 

[brandon429]

what are the key suspect causes of him getting any changes in alk by adjusting fish bioloading?

 

[Randy Holmes-Farley Verified Community Expert]

what are the key suspect causes of him getting any changes in alk by adjusting fish bioloading?

Test error, top off with tap water, decline in nitrate, dosing of nitrate, dissolution of new artificial live rock are about all I think are likely.

 

[brandon429]

Thank you for that, the nitrate portion I wouldn't have caught/reading up now

 

[jasonrusso]

Test error, top off with tap water, decline in nitrate, dosing of nitrate, dissolution of new artificial live rock are about all I think are likely.

Don't think so
Definitely not (I have a RODI system)
Absolutely (the nitrates were very high)
No (I was trying to lower nitrate, not raise)
No (I have all the established rock I can handle, my wife says too much)

Thanks for the help!!