Newbie questions about: RO unit, Cure dryrock, Digital refractometer

[Roberthein]

Hi Guys,

I am fairly new keeping saltwater tanks, although i did have a nano run for about half a year or so, till i killed everything.

This time i have tried to prepare myself best possible, not rush and do what is being suggested in the hobby3. Bought RO unit, cure my dryrock before i start tank cycle, get various test kits, and a (should be) good refractometer and TDS meter.

Lets just jump straight to the questions.

1) Why am i not getting zero TDS out of my RO unit, its a 5 stage, bought from a guy who farm corals etc. he promised this should give me 0 TDS.

https://ibb.co/tPB05jZ

2) Im have dumped all my dryrock in a barrel, with a powerhead in saltwater, and it has been running for about 2 weeks now. Prior to that it was a in a vinegar/water bath for 2-3 days, then rinsed. Rocks are pretty clean fromt the start, but did the process anyway. Question is, my TDS meter measures insane levels (see image above) is that OK? just leave it? or should i replace the water weekly? I planned to leave it in the barrel till its tank ready.

3) When i try to measure salinity, im using a hydrometer and my digital refractometer, i really dont understand the readings.. the hydrometer, says its OK? But the refractometer, show 01.2ppt

https://ibb.co/wCFG6Ft

 

[Sk8r]

Wow. Well, eiither you have the world's worst water or the ro/di unit has a problem. Did you buy it fully assembled? Did it come with the cylinders already packed? Possibly there's a tube misrouted, or a cylinder that's not working right...honestly, hoping someone else chimes in here. The other possibility is a wonky tds meter. Best rule is to suspect the test kit FIRST, and be sure that's right. Test it in distilled. Go to that guy and ask questions. The rocks, now, are just going to soak, and probably have a lot of dust.

Try this: you have a marine salt mix, right? Look at the mixing instructions. Mix up one gallon of salt water exactly as instructed (usually it's 1/2 cup of salt to a gallon of water.) Test that. It OUGHT to be reading 1.024, after 24 hours to really mix. Dissolving takes time! (Mind, I don't do fish-only salinity, so fish-only salts are a mystery to me. I'd expect, however, that 1/2 cup to gallon ratio.)

Stay with us. There's a sane answer in here somewhere, but first go back to the guy and let him help you 'calibrate' your salinity tester, and likewise show him these pics. You're not stupid: it's not you, so don't be embarrassed to ask. I suspect either a malfunctioning tester or something 'off.'

Our Reef Chemistry section also has some helpful people. Message bertoni, and see if he's got an idea.