RO unit coming, need advice

[DongShenYin]

Ok guys, I finally broke down and bought a RO unit from Aquatic Reef Systems. (For less than my bugeted $150, yay!) It's due here on Thursday. I'm going to use a faucet adaptor and hook it up to a sink. The Hannah TDS meter reads 46 for my water... since I have a 7g nano and don't plan on using the RO unit for anything else, how often do you guys think I should change the filters? Once a year? With the TDS so low, do I need a DI unit? I assume the RO unit will come with instructions, but any tips on what and what not to do? Thanks

 

[dnjan]

My water (seattle) typically has a TDS reading in the low 30's. I use RO-only, and have 0 to 1 coming out. So, set your RO unit up, collect a few gallons of RO water (to get everything broken in), and then collect a sample and test it. I would say that if your TDS is 0 to 2, you don't need to spend the money on DI.

Concerning when to replace the RO membrane - bought mine in 2000, collect about 7 gallons per week, and have not replaced the RO membrane yet.

 

[clarkii]

Yay, well done on the RO unit, I think it is one of the nasties to have in keeping saltwater tanks and nano's in particular.

Very straight forward to add the water supply under the sink, the instructions will show how to do it and the unit may even come with the adapter to fit it.

With a TDS reading of 45 you are very lucky, I live in the UK and have readings around the 400 mark before the RO/DI and about 3 on the output. With the unit being used so little and the remarkably low TDS level you have on the water I would think that you would not need to replace the filters for a couple of years. You will be able to see the TDS rise slowly when the membrane/filters begin to age. With the low TDS then the filters will take a very long time before they begin to fail and clog up.

A DI unit as they are so cheap and so easy to add to the RO unit ( just put in-line after the final filter which will probably be the membrane ) I think is a good idea and worth the money. The DI filter would need to be replaced yearly to 6 months with the good water you have. Make sure you monitor the TDS on the o/p regalely so you can keep and eye on its performance, one thing I think many people fail to do is to monitor the quality of water from the unit often, some people think the RO filters will last a life time which of course they don't.

HTH