I currently have a 92 gallon salt water FOWLR and have used well water and not RODI water. My nitrates are high and I have brown alegae. I am setting up my new 150 gallon tank and bought a RODI unit and want to switch to RODI. The fish store says when I tranfer my 92 gallon contents (rocks, media, sand and fish), I should tranfer the old water as well. He says that is what the fish are used to and if I start with all new water, it could possibly kill the fish. That will result in about 50% old well water and 50% new RODI water as my sump is 38 gallons. Does the old water help with the transition and bring over valuble bacteria and help to not cause a cycle or instead, am I just going to bringing over bad water to my new tank with no benefit to the inhabitants? I always thought the water held no good bacteria and my water has diatoms now so I want to start off on the right foot.
Switching from tap water to roi
- Thread starter JMENZ
- Start date
Its a slow process. Your LFS is correct. No abrupt changes. One 25 percent bi-weekly change at a time. Your system will slowly improve. How high is high concerning NO3? Also you may notice that your DI resin will deplete quickly since your on a well. I've read this on RC. You may want to do a search here. We did a switch from a 55 to a 125 and replaced all the sand. How old is your system? If its fairly new you may be able to reuse it. Ours was several years old. One of the key reasons new fish die is going to a switch in chemistry that's very different. Some of the old water can't hurt.
Last edited:
gone fishin
New member
You're correct the water contains virtually no beneficial bacteria. I would personally start up with all RO/DI water. I would also be suspect of any other advice that the LFS guy gave you.
Thank you both. Two opposite opinions. I will have to check my nitrates again soon and let you know how high. As for well depleting the DI quickly, I will have to look into that too. I do have a full house water filter so I hope that helps some. However my PSI is low so I am waiting on a booster pump before producing RODI.
+1 for what Tony said.
Read this about well water and DI resin.
http://www.reefcentral.com/forums/showpost.php?p=24330995&postcount=5
Read this about well water and DI resin.
http://www.reefcentral.com/forums/showpost.php?p=24330995&postcount=5
If you are worried about switching their water, why not do a couple water changes in the old tank with the RODI water? Granted, I don't see fish having issues if you are only switching from well to RODI... do you bring water from the fish store to dump in your tank when you buy a new fish? Every person's water will be different so as long as the salinity and temp are the same (and obviously the tank is not high in ammonia etc) I see no reason the fish would show issues of the water source switch in general.
I wouldn't want to bring old problems to the new tank if you are thinking the well water is your issue. The other thing is, if you are bringing the old rock and cure the new you should not see a big cycle. The only concern may be the sand but if you rinse the sand well I don't even think that will cause issues. The bacteria will be in your rock, not the water.
I wouldn't want to bring old problems to the new tank if you are thinking the well water is your issue. The other thing is, if you are bringing the old rock and cure the new you should not see a big cycle. The only concern may be the sand but if you rinse the sand well I don't even think that will cause issues. The bacteria will be in your rock, not the water.
crocogator106
New member
How long do the filters last in a RODI unit using tap water? I was looking at buying the 75GPD unit from Bulk Reef Supply but still have alot of dry rock curing to do before needing the filtered water for my initial tank setup.
CStrickland
New member
Depending on how you transfer the inhabitants, I think you can get the best of both worlds. Fishchef is talking about an easy transition for the animals, Tony is talking about not having any unfiltered water in the new tank. Both could be possible if you can acclimate the critters to the new water carefully. Something like getting the new tank up with rodi water, seeding it with some of the rock from your current tank, and then gently acclimating the fish.
You might want to run carbon or a polyfilter for a while to remove any bad stuff the old rocks soaked up. For example if your home has copper pipes that could have contaminated the well water, or other junk that seeped in from the ground.
Some wells produce water high in CO2, which burns up the di resin. I'm not sure if there's a test for it or what. If it turns out yours does it's just a matter of putting an extra tank between the ro and the di for the water to sit in and off-gas.
High nitrates are common in fowlr, and not really a problem. Also during the move you're probably going to disrupt the bacteria and cause a spike anyway. At least, I did last time I rearranged my rocks. I think it has to be in the 100's ppm before fish are affected. It's more of a coral issue.
CStrickland
New member
The filters wear out at different rates depending on your water. 6 months for sediment and carbon, membrane and di as needed, is a good baseline but each tap is different. Bulk Reef Supply has some instructional vids that explain it. If you still have questions, you might start a new thread so this convo doesn't get confused between answers to your Q's and the Original Poster's.
Welcome!
billdogg
Well-known member
I'm with tony on this X 1000
Try to match basic parameters as closely as you can, and temp within a degree or so. Otherwise I can't think of a downside to using 100% newly mixed rodi.
