If I can use tap water for brackish, what’s about tap water

[pseudechisbutleri]

Title pretty much says it all, I know brackish tanks do not require RO and I know that saltwater will almost never work without RO, but if I used tap water for a brackish tank and I increase the SG of a brackish tank to the SG of a typical SW tank, will I have any problems?

[oceanarium]

Brackish water is the area the salt water meets the fresh water in a river system. Not full sea water salinity.

Tap water vs RO is about impurities things that can cause problems for certain animals like copper, chlorine, flouride etc.

Pete

[pseudechisbutleri]

So does that mean that tap water on brackish fishes would be fine but tap on SW fishes won't be?

[Onsan]

fish are not as sensitive to metals and salts as corals are.
brackish water creatures are some of the hardiest organisms, not because of the extremes they can tolerate but the variability in water parameters and quality.
you're main one really for reef aqauriums is phosphate, to achieve good coral growth and colouration you need very low levels of phosphorous in your tank, adding more through top ups or ASW exchanges just makes the problem greater.

[pseudechisbutleri]

So tap water would be usable if I somehow removed phosphorous?

edit: apparently I can't do that without an RO filter

[Onsan]

no, it can be done with demineralising resin alone, or it can be done with aluminium/lanthanum precipitation, or GFO / GAO filters, but RO is probably the simplest, most convenient and cheapest in the long run.

[pseudechisbutleri]

I'll have to get an RO filter eventually, and I think it would be the best, cheapest and most practical way to go, more practical than the other methods you mentioned (no offence ). In the mean time, store-bought saltwater it is.

[Onsan]

no offence taken, I recommended RO, the other methods are far too complicated for domestic use.