What Are Potential Causes Of Low Dkh?

[Janice]

Can anyone tell me what the potential causes of low dKH could be? We are rebuilding our sabotaged tank (and by the way, the child who poured the bleach in finally admitted to his conduct this week-10 weeks after the 2nd sabotage), and the alkalinity test with Salifert keep coming in under 7, and we have had to dose for the first time ever.

All we have in the tank so far are some corals and some clean up crew-no fish.

32G AIO.

Thanks, Janice

 

[TORX]

What salt are you using?
What size salt are you purchasing?
Have you tested the new salt water before adding it to the tank?

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[Janice]

Instant Ocean Reef Crystals 20.3 kg (5G size container). We have always made sure the salinity was bang on, but in the past we have not tested the dKH, calcium and magnesium before we used it. Colby and I had planned to do that with the bath we are mixing today for tomorrow's water change. Our calcium and magnesium have been high,so I was suspecting there might be an issue with the salt.

 

[Josh]

In your case it will be because of the GFO im pretty sure

 

[Janice]

????? Our PH is 0.03ppm

 

[Josh]

It has nothing to do with phosphates im pretty sure. I dont understand the science behind it however GFO attracts and binds to lots of different things, trace elements, alk, phosphate.
http://www.advancedaquarist.com/2012/2/chemistry

This could explain why @Salty Cracker notices growth right after water changes, if its re-adding the trace back in on water changes then it could explain the spurt like growth if the GFO is reducing the trace elements.

Like i said tho im no scientist

 

[Janice]

I will read the article. Our GFO is Rowaphos.

 

[TORX]

GFO can strip alkalinity.
Be sure you are mixing the salt to the suggested 1.026.
Test the new salt water. Especially if you are using a bucket as some of the mix can settle and the mix will be off.

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[Janice]

Thanks. We do rinse the buckets thoroughly with hot water after each use. I suspect it is the GFO. We may be putting too much in, as we try to prevent algae growth.

 

[TORX]

It isn't the amount, it is the use in general will lower your alkalinity.

I wasn't referring to the buckets before using them. I was referring to the bucket of salt. As it sits, some of the powder settles and the bottom may have more alk at that point. Salt is made up of different powders mixed together and added to the pail, they are not bonded. If the pail or bag is not mixed after sitting for a while, then some of the alk powder can settle towards the bottom of the pail so when you grab a scoop, it isn't an even mix that you are adding to the water.

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[Janice]

OK. Thanks very much for those 2 clarifications.

 

[AdInfinitum]

A fresh batch of RC should run over 11dkh (too high really).
Mixing your bucket should always be done as @TORX suggested. Also IME Alk and Ca tests seem to be the most likely to yield inconsistent results...

 

[Janice]

Sorry, what is RC @AdInfinitum?

 

[AdInfinitum]

Sorry, what is RC @AdInfinitum?

Reef Crystals

 

[Janice]

OK, thanks. I did not know that acronym

 

[AdInfinitum]

OK, thanks. I did not know that acronym

Remember that inscrutable and/or counterintuitive acronyms and jargon are the cornerstone of all professional organizations. As reefkeepers it's up to us to use as many as possible if we ever hope to elevate our group into a truely exclusionary clique!

 

[Janice]

LOL!