Well water vs. RO/DI

[PeeJ]

I know RO/DI water is the best for reef tanks, but what about well water? I have a freind that has a well at his house and instead of buying an RO/DI unit now just use well water. Good or bad?

 

[Anonymous]

hi, peej -- welcome to the board!

i don't know much about well water myself but i'm sure there are many here who will be happy to offer advice.

 

[Len]

It's not recommended. Private water well systems usually have high mineral concentration. Some people use well water filters (ie, water softeners) and the water produced is usable. However, it's a lot safer, easier and cheaper in the long run to just go RO/DI.

 

[Syris]

I can tell you from my own experience that using well water just added to the nutrients in my tank. After a year I got bad hair algae and cyano. I finally got an RO/DI unit and the TDS meter on it reads my well water at 160ppm which is considered low and good for water but it still caused me problems. I did 30% water changes every other day for a week with RO/DI. And now the hair algae is declining but the cyano is going to take longer
I also have a fuge on my system with macroalgae growing for nutrient export and it still wasn't helping.
IMO RO/DI is essential for long term health of the tank. You can use well water but it will cause problems sooner or later.

 

[Anonymous]

Depending where you are well water may be ok. You will need to have it analyzed though or as Len said it could have too high a mineral concentration. The minerals in your water will vary from place to place. Some wells are naturally hard or of; have a high pH or low pH and could have a whole host of other issues. I would have it checked before using it.

 

[jhaag]

It defiantely matters where you live and the condition of your well. I have been using well water for my reef for over 18 months now without a problem. At the same time though, the water next door can have plenty of nutrients. I actually have an RO/DI unit sitting in my closet, but since I don't have enough water pressure, I decided to try just the well water and see what happened. I figured worse case I would need to do some massive water changes with RO/DI. Of course, I also knew that there were very few minerals in my water becuase of the water softener.

 

[Anonymous]

Well, you definitely shouldn't be using softened water in a reef tank! Some wells have high calcium or carbonate concentration (good), while some have high nitrate concentration (bad). As stated, depends on where you live.

 

[jhaag]

I actually have the water softener because there is insane amounts of iron where I live. Of course, maybe that's why my Macro Algea is growing so crazy. I have really been thinking about switching to RO/DI again, but so far, everything is going so great and my tank has never looked as well as it is now. If I ever start seeing any issues, it's nice to know that I have a backup option.