View Full Version : Using tap water to start my 65??

08/25/2006, 05:26 PM
I'm about to fill my new 65 gal and was wondering if using tap water for the start up would be o.k.? Is there a conditioner that I could use to take anything harmful out? I can get R/O water but running a hose into the window would be alot easier. The tank will run for about 6 weeks before I get the LR.


08/25/2006, 05:37 PM
Tap is fine as long as you use a good conditioner. Get one that gets rid of chloramines.

08/25/2006, 05:58 PM
No way, during your cycle you don't need any more contaminants. Use ONLY RO/DI or distilled water.

08/25/2006, 06:09 PM
If I had it all to do over again, I would start my tank with RO/DI. I didn't (started 2 tanks w/tap) and now battling green hair algae. Not saying the water is 100% the reason for it, but whatever TDS was in the tap water certainly helped fuel the algae growth.

Switched to RO/DI, but the battle continues...

Just keep this in mind...while I know we all want to be budget minded, the water qualilty is the #1 thing that will affect whatever you decide to keep in your tank, for better or worse. IME, be cheap on this & then later down the road you're going to be trying to figure out "why is this happening", etc

Just my .02

08/25/2006, 06:20 PM
the big factor is the quality of your tap water. get a tds meter and if its low, less than 50, i would feel fine using it. I suggest getting a ro/di at some point, it makes this hobby so much easier. as long as you plan to run it for while anything in the water will get taken out.

you should not use tap for top off, as you will continually build up whatever impurities are in the water.

08/25/2006, 06:24 PM
you said the "T" word....bad...bad i tell ya!

08/25/2006, 06:44 PM
Whatever.....don't use tap water!!! Trust me with this advice. This hobby is hard enough to get through the first year without problems....don't go looking for them by using tap water. It will be worth the extra effort to get the RO/DI water.

08/25/2006, 06:45 PM

08/25/2006, 07:16 PM
<a href=showthread.php?s=&postid=8013772#post8013772 target=_blank>Originally posted</a> by dcombs44


08/25/2006, 07:24 PM

08/25/2006, 07:38 PM
RO/DI is best, but as Twon8 said the quality of your tap water makes a difference. If you're lucky enough to live somewhere with great tap water, using tap for the initial fill shouldn't hurt anything. I used tap water for ages and never had any algae problems, but because municipal water supply quality can vary from day to day and season to season it always made me uneasy. I bought an RO/DI filter on eBay and feel much better knowing the water going into my tanks is consistantly high quality with no unwanted chemicals.

08/25/2006, 07:59 PM
I would say it definetely depends on your water source. If you live in an area with great water, then you could get away with the tap water.

Test your tap water first, then decide if it is worth using RO/DI.


tang named junkyard
08/25/2006, 08:01 PM
ive always used tap

08/25/2006, 08:07 PM
I have used both, IME, on my system,with my tap water 120 TDS
RO/DI made a huge differance.

08/25/2006, 08:32 PM
Dont do it RO/DI only or you will be making a new thread on


08/25/2006, 08:40 PM
I use tap and have no nuisance algae other than a tiny bit of diatoms (which I don't consider a nuisance). I think the quality of LR and what is hitch hiking in to your system with said rock has a lot to do with it.

08/25/2006, 08:50 PM
RO/DI it's easy and cheaper than buying. with the cost of the things in the tank I would not take the chance. My tap reads 180-240.ro/di 0. this is the only way to go.

08/25/2006, 08:51 PM
hey dont forget to post pics of the tank once its up and running in my thread for 65's....>

I wanna keep this one going.

08/25/2006, 08:57 PM
oh and i use tap water all the time on my tank though i live in an apt building so i'd amagine that the building has some sort of unit that filter the water a bit better. I only believe this because i havent had any problems yet and its been running a good two years. If your planning a reef i would use RO water though if its just for fish it doesnt matter too much. Though i do stress the too much as i would amagine some of the more delicate fish would apreciate cleaner water with out the potential Heavy Metals (ie bonnet head sharks [dwarf hammer head] which cant be in a tank with any metal, not even in concrete tanks with rebar, They can feel the metal and it does something to them).

08/25/2006, 09:02 PM
I too live in apartment, but even when I lived in a house I used tap. I do run a fish only though. Im about to get my first coral so we will see how it goes.

Maybe the water in Idaho is just better?

08/25/2006, 09:51 PM
I'm going for the R/O water in the morning. I don't want to take the chance. Our water is not the best.

>> masterqaz - I've been watching that thread since it was started. I'll post soon as I get it going!

08/25/2006, 10:29 PM
Good choice. You will not be sorry. I used tap water to fill my 60 gallon reef to start with eight months ago and if I had it to do over again I would use ro/di water. It just makes life so much easier. As time goes on, I am using di water and it makes a world of difference.


08/25/2006, 11:16 PM
i have never used RO/DI water for any of my tanks and i have never had hair algae or cyano. I got the diatoms at first but was soon taken care of by some snails. I dont know what my TDS is, but i know i have some sort of water conditioner installed. Im happy with my tap water so far, but will install RO/DI eventually.. lol

08/25/2006, 11:36 PM
I think you guys are too paranoid. Continually using tap isn't the best idea, but starting a tank with tap isn't a big deal. I've done it twice and it hasn't harmed a thing. The Georgia aquarium, and probably every other large aquarium uses tap; it can't be that bad.

08/25/2006, 11:52 PM
Start it out right from the beginning. RO/DI. A lot of contaminants are cumulative meaning they don't go away they just get worse over time so don't add them to begin with.

08/26/2006, 12:26 AM
I used tap and now have algae problems from the high phosphates in the tap water. ro all the way

08/26/2006, 01:42 AM
Even with supposedly low TDS tap water I used RO/DI to start my tank because I couldn't see the logic in cutting a corner on something that important. Worst case scenario is you're paying ~$1 US/gal to buy it from the grocery store and it costs you $60 to fill your 65g tank (after displacement and tax). When you think about it, it doesn't make much sense to spend thousands on equipment/livestock and then use something that could realistically cause you problems down the line.

08/26/2006, 12:44 PM
Im not waiting to buy an RO/DI to save money or cut corners, I'm just a firm believer in "if it's not broken, don't fix it." I will eventually get a unit but it is not on my list of priorities.

08/26/2006, 03:16 PM
I ended up going to the LFS and getting R/O for .20 a gallon. Here's a shot of the tank running...


08/26/2006, 04:38 PM
yeah do not use tap. Ive had three tanks so far, and if ive learned anything..... its do not start out with tap water, no mater how easier it seems.

08/26/2006, 05:42 PM
I started my 72 bow with the Tap Water Filter. It works great. It've been 2 months. I don't see any algae. Make sure you add stress coat to the water to remove chlorine cand chloramines.

08/26/2006, 10:49 PM
I'll bet you $10 your tap water filter was exhausetd the second time you used it. They are good for about 50 galons maximum and thats with good tap water. Once it is exhausted it begins to release what it has collected and actually makes the water worse.