AWC Dazed and confused.

[Auquanut]

I have some serious issues with my new AWC system and could use some advice. Sorry in advance if this gets wordy. I'll keep it as inclusive and brief as possible.
I recently started an AWC system utilizing a GHL maxi as a stand alone unit.
Approximately 20 Novemberish I mixed 55 gallons of salt water using Fritz RPM.
24 November I brought the system online. One of the dosing pumps failed and I had to send it back.
16 December I was back online using the same water (keeping a nano power head in reservoir to maintain flow).
Since then I have been monitoring parameters. Here's where things go sideways.
I'm changing about 1.5 gallons daily in my 125 spread out over 12 applications 2 hours apart.
I expected to have to adjust my dosing schedule to conform to the daily WC.
Alk has slowly risen from 9ish to 10. This is a gradual increase.
Cal has decreased from 440 to 400. Again a gradual decrease.
Mag seems to be holding steady at 1350.
Nitrates initially appeared to increase alarmingly, but have since stabilized and appear to be decreasing.
SG seems to be dead on. SG in the reservoir seems to be perfect.
There is considerable residue in the reservoir.
NSW and ATO usage seem to be about what I would expect. Nothing mathematical, just visual monitoring.
Same goes for Alk and Cal reservoirs. The level on both stay equal.
I'm confused. I would think that precipitation in the reservoir would result in low Alk.
If my water export and import didn't match, I would expect a change in SG.
I'm currently making RO/DI, and I'm going to start over.
Any words of wisdom?
Am I doing something wrong?
Sorry again for the long post.

 

[AZMSGT]

Um... I can‘t see what you‘re asking here. Can you please clarify your question?

 

[P-Dub]

Hmmm, I'm assuming that you have tested the salt mix when freshly prepared? If so, what are the Ca & Alk of those? How long does the precipitate take to form? After the precipitate has formed have you tested the Ca & Alk of the mixed water? If so, how often? Higher Alk will drive down Ca as I'm sure you already know. As well, is the NSW reservoir airtight? If not as evaporation in the reservoir occurs the concentrations of your Ca & Alk will change. You may want to adjust the Ca concentrations of your freshly mixed water to match stasis. You can get precipitation of calcium carbonate due to high alkalinity as you can precipitate alkalinity from high calcium.

 

[Auquanut]

Um... I can‘t see what you‘re asking here. Can you please clarify your question?

Since starting the AWC, Alk seems to be rising while Cal is decreasing and SG and mag stay the same. Not sure why. I'll adjust dosing accordingly, but I don't understand the disparity. I'd like to make the change to Tropic Marin salt, but it's a pretty huge cost difference.

 

[Auquanut]

Hmmm, I'm assuming that you have tested the salt mix when freshly prepared? If so, what are the Ca & Alk of those?

Yes. If I remember right, they were about 450 Cal and 9.3ish Alk.

How long does the precipitate take to form?

I really didn't pay enough attention. The water sat for quite awhile while I was waiting for the maxi to come back. By that time there was already residue formed.

After the precipitate has formed have you tested the Ca & Alk of the mixed water?

I have not. I guess I assumed that I would be able to use the NSW for a considerable period of time with minimal change in parameters.

Alk will drive down Ca as I'm sure you already know.

Didn't take that into consideration. I guess I didn't expect the disparity that I'm experiencing.

As well, is the NSW reservoir airtight? If not as evaporation in the reservoir occurs the concentrations of your Ca & Alk will change.

Not completely airtight, but I've been monitoring SG. It seems stable. No noticeable increase. I'll have to start monitoring Alk and Cal in the NSW reservoir. Just tying to keep this as simple as possible.
Thanks for the input. Things are becoming clearer now.
I'm going to start making and using smaller batches of NSW in an attempt to not have to adjust the parameters of the reservoir. What do you think?

 

[P-Dub]

I have fount that I will do 2.5 gal water change nightly and I use a 20-gallon reservoir. Things have been fairly steady. I, fortunately, have access to natural seawater for my water changes. Oddly, for whatever reason, my salinity would slowly drop over time likely due to skimming, evaporation, and Nano-micro bubble scrubbing. To combat this I take out 2.5 gal of water for every 2.76 gal I replace. It's weird but it works. Test the mix after a few days and see what the numbers tell you. Temperature will also affect precipitation. Only one run of testing over a week or so should tell you what is going on in the reservoir.

 

[Randy Holmes-Farley Verified Community Expert]

Precipitation takes out 2.8 dKH for each 18-20 ppm of calcium,

 

[Auquanut]

have you measured the new salt water you are using? Some folks have complained about Fritz variability

I did. If I remember, it was about 450 Cal and about 9.3 Alc. It sat for quite awhile with a nano power head while I was waiting for the maxi to be returned.
I'm seriously considering changing salts.

 

[Randy Holmes-Farley Verified Community Expert]

In general, awc doesn’t alter alk and calcium much, but will make little tugs toward the salt mix.

don’t over interpret what may also be test error/variability