Saltwater

[snake65]

I know this sounds stupid and I have tested with 2 different kits. The salt in the main tank 400l is 1.29 and my sump is 1.25. So which one should I aim to keep correct.
Tia.

 

[Journeyman]

The sump and main tank should be the same. 1.026 is closer to nsw.

 

[Kristophf]

What are you using to test?

 

[BadFish619]

Weird they would be different. It's a circulating system.

 

[snake65]

Yes agree to all weird, I used a hydrometer, that I calibrated with distilled water and a brand new refractometer.

 

[cracker]

This is a mystery !

 

[Kristophf]

Is it a new sump? How long has the system been running? I dont think ive ever even tested my sumps salinity, i guess its more important your DT is correct

 

[snake65]

It's about 3 months running and it's the only real issue, I thought maybe the hydrometer but checked today with the new refracto and the same situation so not a mistake any one else tested both?

 

[Kristophf]

Well 1.029 is too high to begin with you should definately be aiming more around 1.025 give or take. Also advised you get a calibration reagent liquid so you know your calibtrated properly

 

[snake65]

I know its to high , I have now got it to about 1.027, that's what you are supposed to use distilled water it's at its purest and my refracto is spot on 0 with it.

 

[Kristophf]

Well you can trust a bottle of distilled water or you can go with a solution that has been designed specifically to calibrate a refractometer to exactly 35ppt. I used the water method for years with no real problems up until recently and decided to try it and i was off by a few notches. So turns out ive been running my tanks lower this whole time

 

[snake65]

Do most lfs have that because I'd like to try it.

 

[Kristophf]

Yea we have it here in Oz pretty sure most places have it if not online for sure

 

[snorklr]

equally stupid question....do you have an automatic top-off feeding into the sump?

 

[snake65]

Yes I do why

 

[Mastiffsrule]

We need to stop using “stupid questions”. If there was an award for stupid I would get it. We are all here for questions of any level.

Anyway, if you have an ATO that is dosing your sump with rodi, that may create a difference for a short period of time until all the rodi gets mixed in. Otherwise there is no way they can be different I can think of. The same water goes up that comes down. (Unless it evaporats at an incredible rate in the dt before it hits the sump since it is 500 degrees)

And did we say Welcome

#WelcometoR2R

 

[snake65]

Well I got the Display to the correct level and now they are. the same will monitor next few days and see if it changes. I know I was measuring correct .

 

[Mastiffsrule]

I am sure you were measuring correct. Just let a good amount of time- depending on tank size, sump size, flow rate before you check to make sure any rodi topoff is mixed in from sump

 

[EmptyWallet]

Yeah my guess is (for future readers to help) either the return flow from DT to sump is so slow that the RO from ATO is dropping salinity OR you are doing something different when measuring salinity between the 2 samples - i.e. perhaps using a different syringe for DT than Sump and the syringe for DT has some residual salt in it, increasing the salinity. I had frustrations in the past trying to match my DT with my QT, only to realise it was due to using different syringes (as you need to isolate all QT equipment). A few squirts of RO through both syringes and they matched again from the same source.