Tap or Filtered Water for a Reef?

[axe_man16]

I would say that everyone on here will tell you RO/DI only. There are people that have used tap water and were lucky enough to get away with it, but for the price of an RO/DI unit (<$300) I would never use any other source of water.

It may be fine for a while using tap water but you will get alot of algae growth and eventually the dissolved sollids will build up and likely kill valuable corals and probably fish.

So use RO/DI from the start! Hope this helps

[BC564]

I use tap water still to this day....been reefing for about 4 years........but I do plan on going to RO/DI once I get the sump moved to the basement and the fish room setup and automated......you will see the thread for that one

[asylumdown]

I haven't been able set up an R/O system in my current place (condo, no basement, storage room has no water access, tank's on one floor, kitchen's on another, spouse would kill me if I consumed any more of our limited floor space, etc.) so I've been using tap water on my 90 gallon for the past year.

My experience in Calgary has been that sometimes our water is great for a reef tank, and sometimes it's not. It's way better in the winter, but as soon as the snow started melting in the mountains, I had a crazy diatom outbreak, and our tap water was testing pretty high in silicate. Then within a few days of any heavy rain in the summer, I would have small cyano outbreaks. I learned it was better to not change the water if it had been raining a lot and wait for a couple dry days. Unfortunately there weren't many of those last summer.

Unfortunately, the acceptable levels of phosphate and nitrate in drinking water are way higher than what's considered safe for a reef. Most times my tap water test kits don't show any detectable amounts of either in our tap water, but I don't use expensive tests for those ions, mostly because my tank always tests undetectable because any extra is immediately consumed by algae. I can tell there's a nutrient problem with the water I've used based on what's growing in my tank.

My next tank will be R/O only for sure.

[Patty-Brent]

I use tap water from a well and have never had any problems with my tank which has been setup for 2-3 years. My fish are happy colorful and my corals are growing fast and are very colourful.

[Cliff]

I am using RO water. I know poeple who have had sucessful tanks using both ro and tap water.

IMO, RO water is a better option for a reef tank, and it would not matter too much for a FOWLR tank.

[kien]

As already stated numerous times before me, there are people who are successful with tap water and with RO water, reef or FOWLR. This is one of my favourite tap water Mixed Reef tanks. Mind you, he has recently switched over to using RO but was very successful with tap water for a long time and never had any issues with tap water in his reef (that I'm aware of).

So yes, you can use tap water successfully so long as you are doing everything else right The one big downside to using tap water though is its consistency as was mentioned. Ultimately if you use tap water you don't really know what is going into your tank. Whereas if you use RO, you know that it is water, period (so long as your TDS is zero). I think this is the biggest reason for using RO.

[globaldesigns]

I RO my water, personally I don't feel DI is worth it. I have a TDS reading of ZERO with just RO filtering. Why take a chance of algae, you may have enough issues with beating the algae without adding tap water to the equation.

[Rogue951]

I use RO water, my TDS meter reads 0 so that's good enough for me.
Tap water is somewhere between 5-10.
I have noticed in my earlier days of reefing that when I used to top up my tank with a cup of tank water I almost immediately noticed a bloom of hair/film algae and diatoms.
so since then I've invested in a filter.

It also has to do with what the water goes through to get to you.
If you live in an old area with old pipes no matter if the water coming in is crystal it's going to leach into the water. so those who use tap water and have no problems are extremely lucky.

In Vancouver we are said to have the best water in the world, and I believe it too. however in a recent news story it showed how despite city testing at the plant, some areas with old/poor piping had severe water problems including smell and discoloration.

I guess what I'm trying to say is RO eliminates any doubt and inconsistency in water parameters.