RODI (1 Viewer)

[Reefdad]

I am looking for opinions on RODI units that will be used for drinking water and tank water. My tank has been running for around 10 months and I am still getting diatom blooms. I am currently using commercial RO water, Red Sea coral pro salt, skimmer, carbon in a small reactor, and frequent water changes, so my guess is that the silicates are coming from the water? Nitrate and phosphate measurements have been minimal and no other algae survives including macro that I have tried without success under different lights in the sump. Tank is really doing well except for one of my galaxias’ whose polyps appear to be surviving but will not expand. Thanks, Dave.

 

[NarnyTheGreat]

Silicates could be in the sand... a lot of sand is made of silicate but there is no documented proof that it comes from there so most people dont give it much thought. Do you know where your sand came from?

 

[Reefdad]

That was my initial thought. i believe it was Nature's Ocean Bio-Activ Live Aragonite Reef Sand or something similar, I didn't realize at the time that everything done to a tank should be thoroughly researched. However, at first I was using distilled water and don't remember the blooms being so frequent.

 

[TXSea]

What is your TDS showing on the PPM for the water you have been purchasing? I have my own RODI unit and it tests 0 PPM.

 

[Reefdad]

I haven't tested the RO but I'm pretty convinced it isn't measuring 0 TDS, and I've been wanting to purchase a RODI for a while and haven't pulled the trigger. Looking at the Typhoon III from airwaterice, the Reef/Residential from Buckeye, and spectura pure models.

 

[TXSea]

I bought mine used for 25 bucks but then I had to replace all the filters, the membrane, and the DI resin for an additional 75 bucks. They are totally worth it in my opinion. At least you know that you are getting what you pay for when you make it yourself. I was in the same boat as you and would buy my water premixed and had diatoms from time to time. I decided to test the water finally and it was reading 59 ppm. Someone hadn't been changing their filters regularly. You should be able to use the same filters for at least a year before change-out. The DI resin is usually good for about 200 gallons and only cost 8 bucks for a lb. of it. I get about 3 refills of DI for 8 bucks! 75 bucks a year is not a bad deal

 

[TXSea]

Also, if you can, get a 4 stage unit with DI. It doesn't matter really what unit you go with but rather the filters you put in it. Mine is a 75 gallon per day unit.

 

[Kabuto]

Nothing fancy is needed. You need a pressure meter to see what your incoming pressure is. You need a TDS meter to check incoming, after RO, and after DI readings. This will let you know how it is working. Buckeye is a sponsor and Russ has been great anytime I had a question.

 

[mwilliams62]

I too was thinking about purchasing a RODI unit untill I was told how long you have to have your watering running (10-12hrs) to get 35+ gallons and I would be afraid to see my water bill if I had to run my water for that long of a time.

 

[trb]

I too was thinking about purchasing a RODI unit untill I was told how long you have to have your watering running (10-12hrs) to get 35+ gallons and I would be afraid to see my water bill if I had to run my water for that long of a time.

It is not like you have it running full blast. I think the ratio is like 3 to 1 or so, that means for every 35 gallons of RO/DI, you would "waste" 105 gallons. It is still much cheaper than paying for water and then lugging it from the store.

I just calculated it based on my approx water cost. 140 gal x 0.008 per gallon, = $1.12 for 35 gallons of RO/DI water.

 

[mwilliams62]

I too was thinking about purchasing a RODI unit untill I was told how long you have to have your watering running (10-12hrs) to get 35+ gallons and I would be afraid to see my water bill if I had to run my water for that long of a time.

It is not like you have it running full blast. I think the ratio is like 3 to 1 or so, that means for every 35 gallons of RO/DI, you would "waste" 105 gallons. It is still much cheaper than paying for water and then lugging it from the store.

I just calculated it based on my approx water cost. 140 gal x 0.008 per gallon, = $1.12 for 35 gallons of RO/DI water.

but what does your water bill show gallons used and your monthly cost ?? I spend close to maybe $18 to 20. a month going to the store getting 70 gallons a month not always the same month to month vs 280gallons on your water bill using a RODI system wasting 210gallons of water?

 

[trb]

That is something you would have to calculate using your water bill details. For example, if we use about 10,000 gallons in a month, then my water bill is about $80. That is 0.008 cents per gallon x 280 gallons = $2.24 of additional water used on my water bill to make that same 70 gallons of RO/DI. I guess you are paying about $0.29 a gallon for your water? That is a good price, but still more expensive than the $0.03 cents that I pay for the water I make.

But then you do have to add in the cost of filters and the RO/DI filter system. If your filters only last you say 500 gallons (and that is low) replacing them every 7 months, that would make your water run about $0.13 per gallon. You could probably go longer between changes. I figure the filter system is an investment in not having to run to the store every week and lug in 40 lb buckets of water from the car to the fish tank. But even if you amortized the filter cost of $200 over two years, that is only an additional $0.12 per gallon for those 2 years. That is still only a total cost for me of $0.25 per gallon, and I don't have to drive to the store (gas $$$) and hassle with the buckets.

All in all, IMO it is very well worth it just from the transporting water issue. Plus you know that the water is true zero TDS RO/DI water, and not something higher. I suspect that if you are only paying $0.29 per gallon, that is is only RO water and not RO/DI.

 

[mwilliams62]

True I will have to pull out my last water bill and go from there. Because I hate lugging those containers from the store to home.
Thanks

 

[trb]

Oh, and FWIW, I paid $100 for my used RO/DI system with almost new filters. I've used it for over a year and probably made 900-1,000 gallons of water, and it is just now creeping up to 1-2 TDS on my TDS meter. So my total cost for water this past year has been about $0.11 per gallon, including amortizing the cost of the filter over 12 months. After I change my filters soon, ($60) it will then only cost me about $0.07 a gallon if I get another 1,000 gallons from it, and my RO/DI system is fully paid for.

 

[andrew7b]

You can add a booster pump to help make the water half the time.

 

[RR-MAN]

You can add a booster pump to help make the water half the time.

And waste less water. My RO/DI unit has a ratio of 1:1.5

 

[Buckeye Hydro]

Folks - don't consider adding pressure as a magic way to reduce waste water. If you add pressure, you may also need to tweak your flow restrictor. You want about a 4 to 1 ratio of waste water to purified water.

Russ

 

[ange062]

I use the BRS 5-stage system. Make sure you get something choloramine specific for Houston, almost all of the water plants around here have switched by now.

http://www.bulkreefsupply.com/store...pd-ro-di-5-stage-chloramines-plus-system.html

Works great, I get 10TDS out of the RO and 0TDS as expected after the DI. I use it for drinking and tank needs.

 

[Andy]

I use the waste water for my pool. Nothing goes to waste.

 

[toefu]

how does one know if their water has chloramines. I just changed the filter of my rodi recently when the tds made it to 20. This seemed a bit quick considering i've used perhaps 700 gallons or so. I've looked at the city water report for chloramines and it does show some, but is this what people are saying is "chloramine" in the water?

http://www.westu.org/modules/showdocument.aspx?documentid=987

Thanks.