How to automatic mixing water

[lastlight]

Originally Posted by sphelps

I don't think it's reasonable to assume most can store 200 gallons of water, I've seen a 200 gallon poly tank and it's big and I can't see many people finding a convenient location for it. Some would even have trouble getting it inside.

Yeah it's not practical for most but I'm designing a fishroom and may create a spot for one.

[abcha0s]

I'm going with the ~200 gallon storage container. I'm looking at the LiterMeter III peristaltic dosing pumps for the Continuous Water Change. The pumps are calibrated by volume, rather than time so minor differences in pressure can be accomodated. The ATO runs independantly and has nothing to do with the water change system. It's an incredibly simple system.

However, the purpose of my post was to share my experience with salinity probes. They are increadibly sensative to stray voltages and tend to wander all over the place. Curt at Apex recommends that the salinity probe be placed in a drip cup to completely issolate it from the sytem. I was never able to get a consistant reading from my probe and basically threw it out.

Another concern is the mixing rate of new saltwater coming in with tank water. I use this concept to monitor the pH of my system when topping up with Kalk saturated water. I have the controller set to shutoff the Kalk ATO when the pH hits 8.4 - However, by the time the pH sensor reads 8.4 the pH in my tank is past 8.5 - There is a delay in the reading but it's also partly how the kalk saturated water mixes into the tank and where the probe is located.

IMHO - I wouldn't trust a sensor to control/maintain the salinity in my tank. I think that you will be constantly adjusting minor fluctations in salinity either up or down. If your not careful, you may get a bouncing effect.

I also woudn't trust a cheap dosing pump. Thus, I'm prepared to spend the money for a high quality balanced pump setup.

[wolf_bluejay]

Originally Posted by abcha0s

However, the purpose of my post was to share my experience with salinity probes. They are increadibly sensative to stray voltages and tend to wander all over the place. Curt at Apex recommends that the salinity probe be placed in a drip cup to completely issolate it from the sytem. I was never able to get a consistant reading from my probe and basically threw it out.


IMHO - I wouldn't trust a sensor to control/maintain the salinity in my tank. I think that you will be constantly adjusting minor fluctations in salinity either up or down. If your not careful, you may get a bouncing effect.

I also woudn't trust a cheap dosing pump. Thus, I'm prepared to spend the money for a high quality balanced pump setup.

Grumble, grumble -- Ok, I have to admit, you are right on this -- a lot of the idea of using the controller really depends on getting a probe that accurately measures things. The delay in measurements is not a big deal as you could just have delays put into the pump cycle -- pump for a minute or 2 -- wait 10 -- check ph, repeat.

But I could see most of these probes being affected by stray voltage, calibration drift, and general crappiness that would cause the system to mess up the tank parameters big time.



Has anyone done the math on how much the salinity would be affected over time by not using "matched" pumps? If oyu have 200 gal tank, doing 2 gal a day water change, and the pumps are out by a bit --- how much would things get out of whack over the whole ~200 gal water change?

[sphelps]

You don't need to match pumps if you use a float, I posted an explanation earlier involving a slow fresh water top off and a fast saltwater top off. Using such a method will result in stable levels.

As for conductivity probes they do fluctuate in my experience as well but with the right controller you get use to quickly adjusting the calibration/set points on a weekly bases to maintain consistent salinity.