[jckmc]

Good afternoon,

I'm the engineer on a 33m motor yacht in Spain, and I'm fed up of water spots. I'm looking to work out a solution to reduce the TDS in my dock water to an acceptable level without reverse osmosis, is it possible?

We have absolutely terrible water off the dock (450-500ppm, 2.5mg/l Chlorine and 7-10˚ General Hardness). Sadly I have no access to power besides 380v from the shore box, and have little in the way of budget to work with (can't spent €5000 on a mobile RO unit). There's a company in the States called CR Spotless who do wash down systems for cars - their XL model appears to be 2x 4.5x20" filter housings full of their proprietary DI resin. The unit is around $500 and they claim that even with water coming in at 600ppm, I can get 2000lt of water with a TDS of 0 before it's time to change. I'm quite skeptical as I already have an 11lt Pentek softener vessel with mixed-bed resin, with a pre filter set up consisting of a 3µ silver-ceramic cartridge and an activated carbon core, and get a minimum of 380ppm TDS out of that. The hardness is reduced to an undetectable level, sure, but the Mg/Ca has just been replaced by Na which still makes water spots.

My questions are;
a) Has anyone got any experience with the CR Spotless systems?
b) Is the company talking nonsense saying I can get TDS 0 purely with DI resin?
c) How can I improve my set up to reduce the water spots after a wash down?
d) Would I benefit from a different resin/second vessel etc?

Many thanks in advance.

Jack
C/E, Motor Yacht Harmony 1

[Og]

Use a second vessel. Rotate them.

[Tosh]

Are you sure it's not just salt from sea-water? Assuming it's in a marine environment.


Yes, you can get a reading of 0 from just D.I. but if the source water is hard (which your readings suggest it is very very hard) it'll take more resin to achieve this, so more costly and a need to have more vessels to run your water through.

[P @ F]

Why is RO not an option ?

[P @ F]

And surely more to the point , if the owners of a 33M boat cant afford to buy this washdown system off the shelf then i think either , they are not worried about spots, or they are on the bones of their behinds 

Rich

[jckmc]

Thanks all for your replies. I'm going to investigate a second vessel and test the output from that.

We have a SeaRecovery RO system on board for making fresh water from sea water. It's a fantastic bit of kit (outputting <350ppm even from marina water), but has a very slow flow and I'm not able to plumb in into a fresh supply sadly, hence the need for a portable DI system.

Will post my findings here.

[andyM]

Thanks all for your replies. I'm going to investigate a second vessel and test the output from that.

We have a SeaRecovery RO system on board for making fresh water from sea water. It's a fantastic bit of kit (outputting <350ppm even from marina water), but has a very slow flow and I'm not able to plumb in into a fresh supply sadly, hence the need for a portable DI system.

Will post my findings here.

You might find it more convenient to purify the water into a holding tank as many of us do (IBC tank or similar).
Then the time it takes to purify won't be an issue as you won't be needing to use it on demand.

[Marc Stock]

Thanks all for your replies. I'm going to investigate a second vessel and test the output from that.

We have a SeaRecovery RO system on board for making fresh water from sea water. It's a fantastic bit of kit (outputting <350ppm even from marina water), but has a very slow flow and I'm not able to plumb in into a fresh supply sadly, hence the need for a portable DI system.

Will post my findings here.

You might find it more convenient to purify the water into a holding tank as many of us do (IBC tank or similar).
Then the time it takes to purify won't be an issue as you won't be needing to use it on demand.

Thats not going to be suitable. The ro water unit id imagine is for drinking water only, as there is already a holding tank  for on board showers and taps. You wont be able to hold drinking water in a large tank it wont stay good for drinking.

I know this because we owned a sea boat for 15years before dad sold it.

[Spruce]

Thanks all for your replies. I'm going to investigate a second vessel and test the output from that.

We have a SeaRecovery RO system on board for making fresh water from sea water. It's a fantastic bit of kit (outputting <350ppm even from marina water), but has a very slow flow and I'm not able to plumb in into a fresh supply sadly, hence the need for a portable DI system.

Will post my findings here.

You might find it more convenient to purify the water into a holding tank as many of us do (IBC tank or similar).
Then the time it takes to purify won't be an issue as you won't be needing to use it on demand.

Thats not going to be suitable. The ro water unit id imagine is for drinking water only, as there is already a holding tank  for on board showers and taps. You wont be able to hold drinking water in a large tank it wont stay good for drinking.

I know this because we owned a sea boat for 15years before dad sold it.

I got the feeling that this is a slightly more complex subject than it seemed to be at first.

I have been following one of the yachts on YouTube, Emerald Steel. They fitted a water maker. They talk about being happy with the pure output of 350ppm as its drinking water.
They use a 40" membrane but it has a smaller diamt and doesn't produce water very fast. The also have a high pressure pump feeding this.

https://www.youtube.com/watch?v=Q4Jdq6XRdj4

https://www.youtube.com/watch?v=JDi6Ld5o8ns

.

[andyM]

I assumed he is talking about producing water for washing the Yacht down to reduce hard water spots, and I didn't mention drinking water.
Hence my comment of a holding tank. 

[Spruce]

I assumed he is talking about producing water for washing the Yacht down to reduce hard water spots, and I didn't mention drinking water.
Hence my comment of a holding tank.

Agree.

No you didn't but the op mentioned their water filter that doesn't remove the salt ions so their water still dries leaving spots.

I can't work out if they use different membranes in water makers to what we use for window cleaning.

.

[ray l]

Hello Jack
It shouldn't be to hard to rig a temp ro system from dock water to tanks (not sure charges for water as half going to waste, although you could have ro water to pot tanks ,waste ro would still be good for normal water tanks. Depending on your tank arrangement)
Leaving pot water at a low tds, guest should appreciate nicer water and your  kettles / washing machines should last longer as well.
As temp fixture it wont need to go through code, and keep saltwater maker ro separate. Then just use a di vessel for rinse down.
(I'm working on the assumption of quite a  bit of time tied up)

I hope that helps. Give me a shout if you want more specifics. 17 years at sea so I know some of the problems, didn't have to worry about watermarks in the north sea

Ray

[Spruce]

Hello Jack
It shouldn't be to hard to rig a temp ro system from dock water to tanks (not sure charges for water as half going to waste, although you could have ro water to pot tanks ,waste ro would still be good for normal water tanks. Depending on your tank arrangement)
Leaving pot water at a low tds, guest should appreciate nicer water and your  kettles / washing machines should last longer as well.
As temp fixture it wont need to go through code, and keep saltwater maker ro separate. Then just use a di vessel for rinse down.
(I'm working on the assumption of quite a  bit of time tied up)

I hope that helps. Give me a shout if you want more specifics. 17 years at sea so I know some of the problems, didn't have to worry about watermarks in the north sea

Ray

Ray, why do yacht water- makers need high pressure pumps to exert a force on the membranes of between 700 and 1000psi?  We don't need that pressure to process water with our membranes.

.

[ray l]

Sorry don't know. We carried 150 m3 of fresh water, and I was upstairs wave watching.

Ray