Low Levels or Possible Testing Error

[Randy Holmes-Farley]

I made two another tests:

Ca test on new 5L 1.026 saltwater. Ca:435-440
(Which is very close to AF 35ppt levels)

pH test on my RO/DI water. pH: 4.5-5 ish.

-

Does it explain the low kh levels im having? If so, I can rely on my refractometer and ca levels, and only dose baked b.soda for adjusting kh.
Thanks in advance

No, unless it is not zero ppm tds ro/di. pH meters are useless in ro/di due to the low ionic strength, and totally pure water in contact with air will be acidic from CO2 entering it and forming carbonic acid. None of that impacts alkalinity.

 

[rishma]

FYI, the ATC has nothing to do with the sample temperature. It corrects for ambient temperature (the temperature the refractometer takes).

The one or two drops of sample instantly take on the temp of the refractometer.

Got it! So float the refractometer!
(Nobody do that please)

I don’t use a refractometer but what you described makes sense. It’s a tiny film of sample water unlike a conductivity probe or hydrometer where the water temp dictates the device temp.

Thanks!

 

[ReneReef]

So float the refractometer!

Good one for April first…

 

[poqokio]

No, unless it is not zero ppm tds ro/di. pH meters are useless in ro/di due to the low ionic strength, and totally pure water in contact with air will be acidic from CO2 entering it and forming carbonic acid. None of that impacts alkalinity.

Thanks. Can you please describe me, what would u suggest for me to move on?

Simply add alk booster (sodium carbonate) for each batch of salt, since Ca levels seems close to reference values?

 

[Randy Holmes-Farley]

Thanks. Can you please describe me, what would u suggest for me to move on?

Simply add alk booster (sodium carbonate) for each batch of salt, since Ca levels seems close to reference values?

In a fallow tank with no corals? I wouldn’t test anything except once in a while temp and salinity.

 

[poqokio]

Fallow is near ending.
I'm asking because I want this tank to be coral-ready, and I think I can adjust the parameters in slow way in order not to stress current cuc invertebrates.

Low alkalinity in current tank and every new batch of saltwater, seem to me requires some action :)

either preventing that low alkalinity with determining the root cause of the problem;
Or dosing an alkalinity additive

But those are my newbie thoughts, and I'm still not sure what to do.
--
Tank future plan:

I'll add some corals (maybe before fallow period ends),
2 captive breed ocellaris clowfish just after fallow, because they are in a closed breeding system with no parasite.

Then, I'll gradually increase coral population (mostly softies+hammer,torch,candycane, duncan).
Maybe a BTA, but im not sure of that.

Also will increasre fish stock with 28 day observational qt procedure. (RG basslet, bicolor blenny, springeri damsel).

 

[Randy Holmes-Farley]

I’d raise the alk to 7 dKH over a few days with baking soda and you will be coral ready.