RODI? advice please

[Tava176]

Hello all. I am in the market to purchase an RODI....or maybe just RO...not sure.

Here are my questions:

1. RO VS RODI
2. If going RO do I need to add chemicals to replace anything removed by RO system?
3. See question #2, but what it I go RODI?

Here are my tank specs:
100 gallon
fish and coral (no hard corals though)
VHO lighting.
recently stopped using FosBan.
Having a lot of green algae
Been using tap water for the last 5 years.

Thank you in advance for the advice. I appreciate it!

[ludiNano]

I would go with RO/DI IMO and im sure most everyone else's.

Unless you changeing your water a ton and useing a very high quality salt mix then yes, and even w/ the salt mix it probly wont keep up with calcium and buffering demands.

I have heard good things from www.bulkreefsupply.com on number of there products.

[birdman1979]

Go with RO/DI. I notice increase in HA in my nano when TDS gets above zero in my top off. My RO reads about 13ppm before DI chamber. Zero after one stage of DI... I use two as a precaution. Easy to build up nutrients in a nano.

[Macimage]

I'd also recommend the RO/DI. It's doesn't cost that much more and your water is one of the most important aspects of a successful reef tank.

Joyce

[Tava176]

thanks for the advice so far. Please keep it coming.

2 stage?? 4 stage?? 7 stage??

Success stories and failures are good to hear.

what do I need to add to the water other than my Instant ocean salt and CA and AK that the RO/DI will be stripping the water of?

Thanks!!!

[AZDesertRat]

Don't get wrapped up in "stages", thats an e-bay sales gimmic, like the more stages the better the unit which is far from the truth.
You need 3 stages for RO and 4 stages for RO/DI, thats it no more no less unless you have specific needs or conditions like very high TDS or other water quality conditions.
A very good unit that wil not set you back a bundle is the 75 GPD Premium system from www.buckeyefieldsupply.com . It comes with very high quality components and filters and even includes things like a handheld TDS meter, RO bypass valve, inline pressure gauge and even an adjustable flow restrictor if you request it so you can get your water ratio set perfectly.
It uses the industry standard 75 GPD Dow Filmtec RO membrane, a very good smal micron range prefilter, and the best carbon block you can buy. The DI is a full sized vertical 20 oz size and is refillable so yopu can take advantage of bulk resin and its associated cost savings.

You need to check with your water utility and ask for a copy of your water quality report so you can tell the RO vendor what you have. If its like some New York waters the silt loading or sediment is pretty high along with silicates and a unit like the MaxCap from www.spectrapure.com may be a better choice. Spectrapure sells a ton of MaxCap units to New York state residents, partly because of the 0.2 micron pleated prefilter they offer which has 10x the surface area of normal filters plus their SilicaBuster custom DI resin.

You add nothing to RO or RO/DI water if you are doing top offs and only a good quality salt mix for water changes. Additives and supplements are a good way to get in trouble and get a system out of balance. There may come a time down the road you need to do calcium/alkalinity adjustments but thats usually way in the future when the system is heavily stocked.
Never ever add anything unless you have a good test kit for that particular element, use it on a regular basis and know for sure it is deficient and needs replacing.

[Tava176]

THanks for the info so far all.

Just got off the phone with my Father. He has a RO unit he no longer uses and is going to send it to me for free along with a TDS meter.

The unit has a 5 micron sediment filter, a 5 micron carbon filter and two RO membranes.

I am then going to purchase the below listed DI canister to attach to it.
Should be good enough for free :) He says he gets down to a reading of 2 with the RO unit and then with the added DI, I should hit 0. He lives in Montana and uses well water that reads around 78 before filtering.

Here is the DI I plan to get...

http://www.bulkreefsupply.com/RO/DI-Filters-&-Systems-RO/DI-Systems/c9_10/p43/Deionization-Resin-Canister/product_info.html

[AZDesertRat]

Because he gets down to 2 from 78 does not necessarily mean you will do the same. You need to know your local water conditions.
A 5 micron prefilter and carbon are pretty coarse, when it comes time to replace them at 6 months get something more like the 0.2 or 0.5 micron prefilter and a 0.5 or 0.6 micron carbon block. Both will do a much better job of protecting the RO membranes.

You say he is no longer using it? How long has it been idle and have the membranes been allowed to dry out? They may need replacing if they have not been in use for awhile.

[Tava176]

He says it has been sitting unused for 6 months, but still has water in it.

I do plan to put new filters in it right away, but will see how the membranes perform before replacing them. He is sending me a TDS meter too, so I will test.

I will hook it up, replace filters, flush it, then make 50 gallons and trash it. Then make 5 gallons and test it.

if it does not work out, then I am back to purchasing this one...
http://www.bulkreefsupply.com/RO/DI-Filters-&-Systems-RO/DI-Systems/c9_10/p366/Standard-75GDP-RO/DI-5-Stage-System/product_info.html

If it does work out, then I have done it for very minimal cost.

guess we will see.