Sea Recovery Watermakers

Considering few if any watermaker companies make their own equipment, I'd say who ever gives the best service in your area.

And I'm not sure we have heard enough evidence against Sea Recovery that the conclusion should be drawn that one should stay away from them. As I mentioned, I for one have had good luck with them over the years.

I have also had good luck with Matrix, Village Marine, Spectra, HRO Systems and one or two others.

Can say that the screen/electronic failures are not isolated incidents. We've just had their British agents around to commission our units which are 5 yrs old (don't ask). Screens are a known issue which has apparently been resolved with newer units, and replacements are very expensive.

I think what irritates me the most is that there is no point having delicate electronics involved - they bring nothing to the party. Originally on our project the salesman had persuaded the captain to have the units remote controlled from the bridge - but without any means of regulating pressure! Guy should have been slapped.

Village marine

Similar problem with village marine.
2 X 2000Gpd units

screens cannot reset the maintenance light.. You can do the maintenance but cannot tell the machine that its been done..
Village wants big$ for new screens.
Cheap solution was to unsolder the maintenance LED.
Still its a poor product and poor support

Not to mention the membranes from Village are not 1/2 as good as Filmtech.
we were only getting 600 hours out of a new set of membranes. did the replacement 2 times with the village stuff.. gave up now over 2000 hours on the filmtech and the water is still around 260ppm

Water maker companies are all pretty bad
2nd Kiwis recommendation on HEM, with the exception of the stupid mounting of the membranes.
Matrix is good also, stupid simple.

Oceaneer

Interesting that you should mention that. The last time I was in talking with the Village Marines techs they said they liked to run their units at 800 psi and not to worry what the flow rate is.
It had always been my understanding that you should adjust the psi based on the flow or perhaps I should say production rate, of the membranes.

I told them if I set my systems at 800 psi I show a production rate over what I would normally consider as my max. rate. They said "No problem".

Comments?

I am under the same assumption as you and that is to apply pressure to acheive a certain product water flow rate. My sea recovery manual actually states that damage to membrane can occur if flow rate exceeds specs.

oceaneer, 260ppm is pretty good. did you get the same purity with the older membranes as well? I am at 370ppm and would like to get it down to 250ppm.

Village is a bit clueless when it comes to overproduction.
We have a red line at 800Psi and 1.2 GPM.
you can over produce with any water maker and destroy the membrane is short order.
As for the PPM values, this depends upon your feed temperature, pressure, salinity... but the PPM from the Village Marine membranes was at the beginning the same as the film tech ones.. then it started to increase until the water was over 500ppm.
If you have a village marine unit, the film tech membranes fit right in (2020 is one of the sizes)

The Village marine pressure vessels are very good, just the membranes and electronics are .....

As for failed membranes.. when they start to go its not reversible. but its normally the first one in line that fails so replace that one and see what happens.

Oceaneer

I've always gone by pressure and have run them 800-850 psi, or less to keep the flow rate where it should be at maximum. For example if you're in brackish water, you'll flow more at the same psi as in true salt..... As the membranes get old, dirty/clogged, etc, the flow rate will naturally go down at the same psi. I've seen people run them as high as 950 psi to get the flow rate they're looking for, but I think adding more pressure is a bad move, yet have no scientific data to back that up.

"I've always gone by pressure and have run them 800-850 psi, or less to keep the flow rate where it should be at maximum."

Actually that sounds more like you set the pressure by the max. flow rate. Which is what I have always done.

950 sounds to high to me as well.

I get the unit running without any pressure, then slowly bring it up to 800psi, watch the product waterflow and see what it's doing, check it, then switch it over to tank from overboard, and as long as the flow isn't over the flow rate I let it go.........maybe bring it up to 850 psi if it's not flowing enough water........but usually leave it at 800......

Same here.

I run an 800 GPD system on land (a postage stamp w/ dock) drawing from water that's just below a reversing falls. During the flood it draws pure seawater, but on the ebb it can get brackish, especially if there's been rain. I set the pressure to 800, but have noticed a few times that going back to check pressures after a couple hours, the gauge is reading 900+. Easy enough to turn down, but I had not thought of the potential for damage. I'm replacing the membranes now because the ppm got high (500+), and I realize that it may very well be because of the high pressures. Looks like its time to lower the auto cutoff pressure, and hopefully catch future pressure spikes before they cause damage.

As always... lurking here provide a good education!

Yes, pressure usually increases as the water goes from pure salt to closer to fresh from what I've seen, so does product flow. I had to make water in pure freshwater during the great loop trip I did because we were too large to fit into marina's for 4-5 days at a time. I was told to run the unit at 100 psi by the watermaker company and watch the product flow to make sure it didn't skyrocket.

500 ppm is not to my knowledge to high a reading. In fact the salinity set point on my units to kick over and send water to the tanks is 550 and I've been told by watermaker techs that up to 650 is OK. Did you try and clean the membranes before you replaced them?

500PPm

Sorry to disagree but I am pretty sure that the World Health Organization standards are bellow 500PPm for Salt. For all of my water makers a reading over 350 is a concern and at 400 we order new membranes.
I think you can start to taste the salt at over 650PPm
Thanks
Oceaneer

This is what WHO says about salt. From: http://www.who.int/water_sanitation_health/dwq/gdwq3rev/en/

"Sodium
The taste threshold concentration of sodium in water depends on the associated anion and the temperature of the solution. At room temperature, the average taste threshold for sodium is about 200 mg/liter. No health-based guideline value has been derived"

(For those of you like me who did not know what the word anion referred to: http://chemistry.about.com/od/chemistryglossary/a/Aniondefinition.htm)

They claim you can taste salt at 200 mg/liter which equals about 200 ppm. such a low reading you almost never see on a marine RO system running in salt water in my experience.

Plus:
"No health-based guideline value has been derived".

So it would there appear that there is no WHO standard for salt concentrations.

Here is what the EPA says about salt in drinking water:

"Why was sodium included on the Contaminant Candidate List?
The issue of sodium posed a unique challenge for the Agency priority setting and contaminant candidate listing process. On one hand, high levels of salt intake may be associated with hypertension in some individuals. On the other hand, sodium levels in drinking water are usually low and unlikely to be a significant contribution to adverse health effects.

This low level of concern is compounded by the legitimate criticisms of EPA's 20 milligrams per liter (mg/l) Drinking Water Equivalency Level (DWEL or guidance level) for sodium. EPA believes this guidance level for sodium needs updating, and is probably low. If a health benchmark for drinking water were established using current information and current drinking water health assessment procedures, it would likely be higher. This revision could establish a new level at which sodium occurrence would not meet the criteria for inclusion on the CCL as a drinking water contaminant of concern. There was insufficient time to complete a reassessment of the sodium guidance in advance of the CCL issuance.

Given the state of the data, EPA faced a dilemma on whether or not to list sodium. A decision not to list would be justified by the fact that much is known about sodium, and it does not appear to be a drinking water risk comparable to other priority contaminants. In fact, this was the logic supporting the decision not to include sodium on the previous drinking water priority list in 1991. However, a decision to list sodium would afford EPA the opportunity to address the confusion surrounding the current guidance for sodium in drinking water."

It sounds to me like there is a very, very small health risk to drinking water with "high" (500 - 1000 ppm) levels of salt in it. And in fact based on some of the new information I've seen on the health effects of salt in peoples diets that may be over blown. So perhaps it's more of a taste issue than a health issue in the end.

Out of curiosity, have you ever tried cleaning the membranes before you change them out? If so, what were the results?

From http://www.engineeringtoolbox.com/water-salinity-d_1251.html

Salinity in Water
drinking water - 100 ppm
restriction on drinking water - 500 ppm
limit drinking water - 1000 ppm
limit agriculture irrigation - 2000 ppm
brackish water - 500 - 30,000 ppm
sea water - 30,000 - 50,000 ppm
brine > 50.000 ppm

Yes I saw that. But it didn't say who or what the "drinking water" nor "restriction on" levels were based on that I saw.