Reverse Osmosis Five-Stage House System - Questions

[Punx]

Ok so I think I have settled on a system to provide water for me over the winter. I've been told by all the sales reps that this system will provide me with clean drinking water that has been drawn from the lake (Lake St. Clair). However, compared to the boat specific systems, this thing is about 1/5th the price... I'm just a little weary due to the price of these. Some of the top Under cabinet systems are still less than $600. Is it just because they are bulkier and meant for a house? Or is the quality not as great as a boat specific system?


http://www.waterfiltersonline.com/de...tage_RO-Pump-1

[Mr B]

Thats only a water filter with a pump on it.

I dont think it will do sea water to fresh, Tho I could be wrong,

Any one else like to comment,

[Punx]

That's a full 5-stage Reverse Osmosis system. Here's another I've been looking at. I think they are identical though.

ClearChoice Premium 5-Stage Reverse Osmosis System with UV Sterilizer

Again, the sales rep said that I can turn the lake water into potable drinking water. I will only be using it for showers and cleaning anyways, but it's supposed to be fine to drink.

[skipmac]

Looked at the data on the link to this system and it only addresses converting fresh water supplies to a potable quality. If it would convert salt water it would certainly say so.

I belive the difference is a fresh water RO purifier works on much lower pressure that a salt water RO system which is why it is so much cheaper. Pretty sure this system would not work in the ocean but if you plan to stay in the lakes then it is a moot point.

If you only plan to use it for showers and cleaning why not use the lake water as is or is the local supply not to be trusted?

[Punx]

This system would only be for the lakes. If that's why the price difference is so different, then I think I'm ok. I don't really trust the current water supply as there are a lot of shady activities in our area in terms of dumping. If these kinds of systems will work for lake water, I should be all set correct?

[skipmac]

Originally Posted by Punx

This system would only be for the lakes. If that's why the price difference is so different, then I think I'm ok. I don't really trust the current water supply as there are a lot of shady activities in our area in terms of dumping. If these kinds of systems will work for lake water, I should be all set correct?

Not necessarily. If the shady activities include pumping oily bilge water into the lake, trying to run that through an RO system could kill the membranes.

Not sure how sensitive this system would be to cleaning dirty water but sea water RO systems are very sensitive to sediment and hydrocarbons among other things. I would check with the maker to get their take on this issue with their fresh water systems.

[Punx]

It's not things like industrial waste and bilge oil. It's mainly water that isn't 100% treated being dumped back into the lake during high waterfalls. I think it's a pretty standard procedure, but I still don't like it.

I was thinking of building a pre filter for all the sediment and biological crap. Then having that go into a holding tank. The RO system would pull "clean" water from that tank, purify it, and send it to my fresh water holding tank. I have absurd amounts of space below the floor (not sure what it's called), so size isn't a huge issue. I think a tank was actually removed at one point, but that's a question for a different thread.

So here's the plan.

1) I need to make a pre-filter to clean all the sediment and biological crap.
2) Store the "cleaned" water in a tank
3) The RO system will pull water from the "clean" tank, filter it, and send it to my fresh water tank, ready to use.

[skipmac]

Originally Posted by Punx

It's not things like industrial waste and bilge oil. It's mainly water that isn't 100% treated being dumped back into the lake during high waterfalls. I think it's a pretty standard procedure, but I still don't like it.

I was thinking of building a pre filter for all the sediment and biological crap. Then having that go into a holding tank. The RO system would pull "clean" water from that tank, purify it, and send it to my fresh water holding tank. I have absurd amounts of space below the floor (not sure what it's called), so size isn't a huge issue. I think a tank was actually removed at one point, but that's a question for a different thread.

So here's the plan.

1) I need to make a pre-filter to clean all the sediment and biological crap.
2) Store the "cleaned" water in a tank
3) The RO system will pull water from the "clean" tank, filter it, and send it to my fresh water tank, ready to use.

This looks like a sound plan. However, even with the prefilter and holding tank I would not run the system in crowded harbors, close to marinas, etc. Too easy for someone next door to pump some oil or fuel spill out with the bilge water which would probably trash your RO system.

[Punx]

Luckily we're only running this in the winter when we're the only ones at the marina We're also on the outside of the marina, and the water we share is with 6 other boats, upstream from the gas & pump-out station. I'll giv-er a shot and report back here with the results.

[skipmac]

Doesn't the marina have water supply to the docks?

[Punx]

We're the first ones in the city to ask to dock over the winter. They shut everything down other than electricity.

[familycruisers]

Price differences you see are the difference between ro filtering and ro desalination.

[osirissail]

The systems you linked to are fresh water very, very low volume and very low pressure. They claim they make 50 gallons per DAY - that's about 2 gallons per hour. You can make almost that with the hand pump PowerSurvivor.
- - The pressure pump being used puts out 160psi to feed the R.O. membrane. If you go to the technical (and it is technical) data for seawater reverse osmosis the minimum theoretical pressure needed is about 400psi. To get reasonable output product water the marine and commercial seawater R.O. systems operate at 800 psi delivered to the R.O. membrane.
- - So don't get your hopes up about that sort of system being usable for seawater R.O. purposes. Simple logic shows that if a $289.00 system worked on seawater all the companies putting together $5k to $8k systems would be out of business . . .

[Punx]

This boat will never see seawater, so I don't need desalination. We use bottled water for drinking anyways, so 50 gpd would be for washing dishes and showering only. Buying a RO for salt water is a huge waste of money for me, as is anything over 100gpd. All I need to do is make 50-100 gallons per day of drinkable water from the great lakes region. I have a full time job, and I sleep 6-7 hours a day. This means I will be on the boat, away for less than 10 hours a day. This would mean i could use 5 gallons of water per hour. I don't think I use this much as it is, and I'm plugged into the system.

[osirissail]

Originally Posted by Punx

. . . so 50 gpd would be for washing dishes and showering only. Buying a RO for salt water is a huge waste of money for me, . . .

Absolutely true - as would buying a fresh water system, like you are looking at, be a waste of money for a cruiser sailing in the oceans or other salt water environments.
- - It would have been nice to know that you are only a "fresh water" sailor/cruiser although this discussion about the differences in the R.O. systems has been very good, especially for potentional cruisers who operate in the "other" environment.