Purchasing RO/DI water from the LFS and salinity

Goob

Reefing newb
I just got my refractometer in the mail today ($28 on eBay) and measured my salinity after doing my 15% weekly water change. I only have a 20G (long) tank and only put in water I buy from the store. Typically I keep 10G of RO/DI fresh water and 10G of RO/DI salt on hand for my changes. The water is kept in 5G Home Depot buckets.

My salinity is measuring at 1.029 after doing the water change. I have a few questions:

-As my water settles, will this number decrease because the water is still mixing?
-Shouldn't the water I get from the fish store be at the appropriate salinity before I buy it?
- Since I need to lower the salinity, should I just take out some water and put in fresh instead?
-Will too many sudden changes hurt my fish? Should I wait until tomorrow?

Also, I heard something about putting an air stone into the bucket before doing any changes. Do any of you do this?

I know I should have had a refractometer sooner, but figured my LFS was giving my good water. I top off at the same point each time but am surprised it's a little on the high side.

Your thoughts please...
 
Sometimes the LFS doesn't get it right. Maybe they use a hydrometer or the kid making the mix was texting is girlfriend and added too much salt, who knows

To correct it in a small tank with livestock in it I would remove 1-2 cups of salt water and replace with fresh water.
 
Sometimes the LFS doesn't get it right. Maybe they use a hydrometer or the kid making the mix was texting is girlfriend and added too much salt, who knows

To correct it in a small tank with livestock in it I would remove 1-2 cups of salt water and replace with fresh water.
Thanks for the reply, Steve. Changing only a couple of cups of salt water will make that much of a difference?
 
Over a few days 1-2 cups in addition to your topping off. Your live stock won't notice the change your only high by 0.003 ppt you could just adjust it to 1.026 right now without harming your livestock. But I would go slow over a couple of days if it were me.
 
They've got you covered, but I was wondering if you calibrated correctly?
I used RO/DI freshwater and got my reading to zero. I had this reading on my first measurement, so I'm thinking it already came calibrated. I spoke to the lady at the LFS and she laughed at me when I spoke about calibration fluid. I only saw a few places even selling it, and most of the refractometers available online (even the more expensive ones) didn't offer it.

Do you think I'm okay?
 
Yeah, as long as it was calibrated, drop the salinity in the pre-mix to 1.026 and then remove a couple cups daily like they said above. I just wantedvto make sure you didn't miss a step because I've done that before, too.

....hmmm...my pH is at 2.37??????
 
I took out about 1G of water last night and replaced with fresh RO/DI. I just re-tested the water and now I'm at 1.026. I'll keep up with the steady maintenance. Thanks for your help, I'm glad I caught this and didn't totally trust the LFS.
 
i must have a good lfs cos i get water from there rather than do it myself and they give me the refractometer with the water sample to prove its salinity
 
I buy RO/DI and mix my own, personally. It's not hard and that way I can use whatever mix to whatever salinity I want. Although my new LFS uses Reef Crystals and mixes to 1.026, also, so if I happen to run out and he doesn't have mix, I can buy pre-mixed and its the same.
 
I buy RO/DI and mix my own, personally. It's not hard and that way I can use whatever mix to whatever salinity I want. Although my new LFS uses Reef Crystals and mixes to 1.026, also, so if I happen to run out and he doesn't have mix, I can buy pre-mixed and its the same.
That's actually not a bad idea. It's easier than having to worry about doing these changes and wasting water each time. Thanks!
 
You don't have to waste it, save it for the next week. But only buying RO/DI is nice because I can mix what I want when I want and I also don't have to worry about dumping pre-mix into my top off bucket. I always make sure I have enough for top offs and then if I need more on the weekend to mix for a water change, I can go get it. Less worry during the week.
 
Our local LFS salinity is usually low because they save money on salt, I would let them know so they aren't wasting money and causing your prices to be higher.
 
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