continuous water change system

[32flavors]

Hi all! I am seriously considering setting up a continuos water change system (hereafter: cwcs) because I'm very busy and very lazy--bad combo, but I want the best water I can get for my tank.

What I am thinking is very basic (I'm sure I'm NOT the first to think of this, but I didn't have much luck with my searches):

1. take a 29 gal tank and silicone in a panel in the center.

2. have a hole drilled in each side very near the bottom; install bulkheads.

3. T-off one of the lines going to the tank; then reduce down and install 2 ball valves (1 for setting a constant drip rate; the other for closing off during service, etc).

4. install lines coming off of each bulk head, also with 2 ball valves for the same reasons.

5. one side of the tank will be a R/O top-off, the other for saltwater replenishment.

6. The 29 will be on a stand behind another 30" tank, which is set up next to the main system and piggy-backs off of the system, so it would be out of view except while in my bathroom and pretty easy to fill.

What do you all think? Any suggestions?

What I REALLY want to know is if anyone has any experience with this type of system?

I will be setting it up at about 12%/week, and I will hopefully be shutting it off 1 week per month for a standard gravel vac cleaning of 20-25%.

I have a fuge with a lot of macro and a skimmer, and I am also planning on adding a RDSB & a coil denitrator.

My fish do fine, but I really want to start collecting and growing healthy coral, including some more rare pieces (I have some Duncan on hold) and more demanding pieces (SPS, etc). This is compounded by the fact that my tastes in fish have shifted to some which require multiple meaty feedings per day.

Glad to hear from anybody with suggestions or experience on this.

THANKS!!
Cheree

[Donw]

That gets the sw in but doesnt get it out. Just dripping in SW is only going to raise salinity. You need to remove it at the same rate its added.

Don

[Kentanner11]

I would go to aquaria central and see what others have set up, or search for it on google.

[dunham16]

why not use two dosing pumps set at same drip rate and set them the same. take old and put new in at same in same size containers and maybe have top off solenoid to shut pumps off when old water container is full.

[Jay Fortay]

Seems like too much effort. I think it is a very good idea, but you are going to make your system much more prone to instability that way. Dunham's idea is a good one also, but that sounds cost prohibitive. Maybe better that you have a separate mixing tank plumbed into your system, and a drain on your sump.

1. add salt and water to mixing tank
2. drain sump
3. fill sump from mixing tank.

(dont for get to turn off all electronics in sump...duh)

I know this doesn't change water constantly, but it makes changing much easier.

[Mr James]

I had thought about, but never dared a similar set up. My idea is to:

1. Drill a hole a few inches above my water line in my sump (in my case a 100g Rubbermaid stock tank)

2. Rig up an RO/DI container with a float valve and a surge tank, all in one.

3. Hmmm. The salt. I haven't gotten past this step yet. The only thing that comes to mind is an hourglass type of thing.

Process. Predetermined amount of salt is in mixing container, water drips in viz semi closed valve, container has air diffuser and mixing pump, hits the "high line" and drains into sump. Water level goes above drain hole and water goes out of the system, down the drain.

I know, needs work.

[Donw]

Originally posted by Mr James
I had thought about, but never dared a similar set up. My idea is to:

1. Drill a hole a few inches above my water line in my sump (in my case a 100g Rubbermaid stock tank)

2. Rig up an RO/DI container with a float valve and a surge tank, all in one.

3. Hmmm. The salt. I haven't gotten past this step yet. The only thing that comes to mind is an hourglass type of thing.

Process. Predetermined amount of salt is in mixing container, water drips in viz semi closed valve, container has air diffuser and mixing pump, hits the "high line" and drains into sump. Water level goes above drain hole and water goes out of the system, down the drain.

I know, needs work.

I pretty much do the same thing. I have a stand pipe in my sump that goes to the sewer. I mix up fresh SW and pump it in 24/7 5 gpd. The mixing is alot more in depth but thats a whole other thread in itself.

Don

[Jay Fortay]

That is about what I was thinking, but i was thinking of mass amounts at one time and not a constant flow. The constant flow idea is really good. are you topping off fresh at the same time. how do you monitor the amount of evap? it seems like you would have to set a timer to change the water, or you would be constantly topping off with salt water.

[Donw]

Originally posted by Jay Fortay
That is about what I was thinking, but i was thinking of mass amounts at one time and not a constant flow. The constant flow idea is really good. are you topping off fresh at the same time. how do you monitor the amount of evap? it seems like you would have to set a timer to change the water, or you would be constantly topping off with salt water.

My rodi water goes into a manifold along with sw and two part dosing. Everything goes through a single tube from my laundry room to the tank.

Don

[32flavors]

I would get the SW out with T'd line coming off a tank line. I have a few as I have sump pump line and a closed loop line which I could tap either going to or from...

It would take a week or 2 to get the drip rates matched, but I think it will work.

The only thing I think might be necessary for constancy would be to put a MJ 400 on the new SW drip line instead of allowing it to be gravity fed as that rate will decrease as the level (and pressure) lowers.

[Siffy]

http://reefkeeping.com/issues/2005-10/rhf/index.php#13

2 Very slow pumps/heads and a timer. The valves will likely clog and slow with time.

[32flavors]

Thanks Siffy!! Great article!!

[buffalo123]

How would you balance the difference between top up Freshwater and the continuous saltwater coming in?

[superedge88]

I would just work to make a regular water change easier. I made it so that my sump is two rubbermaid troughs. One trough is easily cut off from the whole system by turning three valves. I then drain that sump, throw in saltwater and turn the three valves to complete the water change-very easy. If you don't have room for a seperate vat for mixing new saltwater, you can just use the sump and not put the sump back on line untill the saltwater is mixed perfectly.

[webbstock]

CWCS seems a little iffy if you have bad evaporation (as buffalo stated). Your salinity would constantly be changing dependent on the amount of evaporation for that period. IMO it would be better to go with a once-a-day water change (set up with a timer). One of our local reefers does it and it works really well.

[Donw]

Originally posted by webbstock
CWCS seems a little iffy if you have bad evaporation (as buffalo stated). Your salinity would constantly be changing dependent on the amount of evaporation for that period. IMO it would be better to go with a once-a-day water change (set up with a timer). One of our local reefers does it and it works really well.

Continuous water change systems using twin head peristaltic pumps really has nothing to do with evaporation. The ato operates as it normally would. Salinity change is not an issue.

Don

[hyrumbradshaw]

Woah! are you supposed to gravel vac (siphon) your sandbed???

[BWilfong]

Here is what you do.

Get something like a 55 gallon drum or even a 5 gallon salt bucket and plumb it to your existing system. Basically run the bucket (drum) parrallel with your system.

Add another bucket or drum and hook it up to your system but do not run it (close it off with a ball value).

When you want to do an automatic water change. Fill up bucket (drum) system #2 with water and mix salt for 24 hours.

Once bucket (drum) #2 has aged, close the ball valve on bucket (drum) #1 and open it on #2. Now bucket drum #2 is running in parallel with your system.

Dispose of old water in Bucket #1 and refill with new salt and RO/DI.

Repeat (close off #2 and open #1) for another water change in a week.

Instant water changes in less than a second!

[hyrumbradshaw]

or do it like you would acclimate a fish with a bucket of new salt water and an empty bucket and drip the new salt water into the tank and have another airline tube siphon water out of the tank dripping into the bucket, when the bucket gets full empty. THat should be about the same time the other bucket of new saltwater gets empty and mix up some more and do it again...

[BWilfong]

After an extended period of time your "from the tank" lines will clog and you'll end up throwing the salinity off because the "new" water will not stop.

[dunham16]

I install well water filtration systems for a living and we use chemical injection pumps that are somewhat cheap online $100 or so and we use highly caustic solutions and they dont clog often so i doubt saltwater would have much effect. They run at a max rate of 17 gallons per day so as i said earlier have to of these pumps plugged to ATO system. Have as big a container as you want say 2 50 gallons vats.Mix new water in 1 container have second one empty use top off float on empty container. When empty container is full it will activate float and shut pumps off. Then just remix new salt and start again.At 17 gallons per day it would take several days or still you could turn pump down to lower stroke setting to say 10% stroke roughly 1.5 gallons a day it would take a month to make the new vat empty. It seems it would be pretty flexible you could set it to whatever you wanted maybe not real cost effective as it would cost a few hundred to set up but would work. Your normal ATO would operate as normal no change in salinity.

[tkeracer619]

A dual head peristaltic pump is the way to go. One head pumps water out, one pumps water in. 24/7 365

[dunham16]

stenner makes a dual headed pump that would work perfect for around 350-400 dollars. A little high price wise but would work perfect

[Jay Fortay]

I like the peristaltic idea. IT is pretty fool proof. even if you allow it to run dry, it wont ruin the pumps. don't forget when it is all said and done, you still have the evap/top off issue to deal with daily.

[32flavors]

Thanks for all the ideas.... Top-off isn't a problem, as I drip in the amount my tank needs per day also--which changes seasonally but it's easy enough to notice, as I check the sump level pretty much daily.

I sure would appreciate more info on the peristalic pumps though!!

Thanks all!!

Cheree