50 TDS ppm too high for makeup water?

[Brad]

Anyone have experience with various levels of TDS in their H2O? I half filled my 180 with 50 ppm H20 and have the option of using an RO/DI to create 1 ppm H2O but am thinking maybe it's not worth it in real terms to prevent algae growth etc. Thanks for any info.
B

 

[monkeyboy]

Well that depends, what do you suppose is constituting those 50 TDS? PO4, NO2, NH4, pesticides, copper, who knows? It may be OK, but you may regret doing this later if you don't use your R/O. If you've got it, don't skimp and fill the tank with only R/O. HTH

 

[SAT]

I pretty much agree with monkeyboy.

The TDS reading really doesn't tell you much except that your water is soft. Most of the dissolved solids in tap water are molecules you either don't care about (e.g., sodium & chloride) or are actually good (calcium & carbonate). However, you probably have trace amounts of nasty stuff like copper and lead from your pipes and whatever else the water company allows in your water supply. A lot of those things are allowed because they aren't dangerous to mammals, but may still be highly toxic to fish & invertibrates.

Over time you'll be adding a huge amount of that water to your system. You can remove the impurities by changing water, but it's better not to add it in the first place. IMO, it's best to use RO/DI water even if your water naturally has a low TDS reading.