Switched IO to RC salt. Have question.

[Keith A.]

For the longest time, I have been using Instant Ocean for the salt in my 75 gallon reef tank. I do a 20% (15 gallons) water change every other week. I switched to Reef Chrystals about 5-6 months ago to help with the calcium levels in the water. When I was using IO, it would take me 2 1/2 metric cups (20 oz) of salt per 5 gallon bucket of water (three buckets, 7 1/2 metric cups, 60 oz total) in order to maintain the same salinity in the tank. Since I started using RC, it takes nearly 3 1/2 metric cups per 5 gallon bucket to maintain the same salinity. To my knowledge, both IO and RC are made by the same company. Is there a difference in the "potency" (if that's the right word I want to use) of the salt between IO and RC?

Keith

 

[Kurt_Nelson]

I've never used IO, but have always used RC. Not sure what salinity you're mixing to, but I know that to get 1.025 SG, I mix 2 cups salt mix with 3.5g water. Not sure what a metric cup is, but my cup is just a dry measuring cup. IO and RC are made by the same company, but I wouldn't necessarily expect them to mix the same.

 

[Keith A.]

Sorry, I should have been more specific. I try to keep my salinity at 1.024. The cup i use is a standard measuring cup. If I fill the measuring cup, it's about 2 1/2 cups.

 

[Krypt]

Most likely the difference in usage size is due to the amount of other components in the salts. The regular instant ocean has more salt per cup, where the reef crystals has more of the trace elements so you need more of it to get the needed salinity.

 

[cmor1701d]

The extra calcium displaces the salt, hence it takes more of the mix to achieve the same SG. IO is great for FO or FOWLR, but needs to be supplemented for a reef tank. You can eiither buy IO and and calcium cholride and magnesium to that or buy another mixture that has already done that.

 

[Keith A.]

Alright. Thanks for the feedback.