Pre mixed saltwater

I am going to be adding water to a 65g and I was considering buying about half pre mixed salt water and mixing the other half myself. My LFS sells pre mixed salt water for 0.80 and R.O for 0.30. I thought that was pretty cheap. What are the advantages/disadvantages of buying pre mixed salt water if any? Thanks

 

Ask what salt they are using. Most of us are pretty particular as to which salt we use. I mix my own.

 

You don't know if their RO unit is being properly maintained. It's more expensive over the long run than a personal RO unit and mixing yourself. You don't know if they use reef salt or cheap salt, and you don't know if it's mixed properly (check SG and other params before you use it).

 

The only advantage IMO is the fact that you don't have to mix it. I like mixing all my own water so I know what's going in there. If you do buy pre-mixed, I would first test their RO/DI so you know they started with GOOD water. (Zero TDS) Then I would also test their saltwater so you know what kinda levels you'll get from their water.

 

The fish store itself is well maintained and the staff is very knowledgable. A never had an issue with any fish or coral I purchased from them. I figure I'll do half and half to make life a little easier!

 

I agree that making it yourself is best, you know what salt you are using, what water you are using. Not all salts are created equally. I know it's def easier to buy things that are "ready" but I always felt more confident in this hobby doing it all myself so if anything comes up (and it does) I know exactly what I'm using.

Another thing to think about that if you have a reef tank, maintaining your params (ALK/CA/MG) is directly affected by the salt. If you are mixing two different types you may have swings in those readings. If you decide to do 50/50 I would test for your params to make sure your dosing is correct.

In closing, for your tank size I would say you do 5g a week maybe? I would think it would just be easier to mix that in a 5g bucket together all at once anyway? All I do is make 5g bucket of water, throw in a powerhead & 2.5cups of salt. Invest in an RO/DI unit also if you're going reef, it will def save you a lot of $ & hassle down the line.

Hopefully I'm not coming off too strongly, I've just been down that road of buying my water and am so much happier now that I make/mix my own, my tank is also much happier!

 

I would ask them what salt they are using and if it is quality salt, purchase the same salt if possible so atleast there wont be any confusions or parameter conflicts.

 

my lfs mixes to 1.019 so i would still have to add salt before i added it to my tank.

 

very good point, many LFS do this to minimize salt costs, their FO tanks are usually in the .018-.020 which is def not good for corals. The trying to adjust the two salinities of seperate mixes would be a pita I would think.

 

My LFS mixes instant ocean at 1.021. For my tank i need instant ocean REEF CRYSTALS at 1.025. Also, when I tested the RO water from my LFS the TDS was 18. So now I mix my own salt. I know exactly what goes into it, its cheaper in the long run, and I can mix it up whenever I need it rather than driving into town and hauling back buckets of water.

With that being said, If you know the quality of their water, salt, and params, buying pre-mixed salt water would work just fine for your tank.