Dosing Limewater

AllSignsPointToFish · Oct 18, 2017

I'm interested in changing the way I dose calcium hydroxide to maintain a more stable alkalinity. Currently, I just add about 1 teaspoon of calcium hydroxide to every gallon of makeup ATO water in my reservoir. I ensure that the water is well-mixed before adding it to the ATO container.

However, here's the kicker. I lose about a gallon per day, some days more, just through evaporation. I'm concerned that every time the ATO activates, I get a swing in alkalinity. I have not been able to measure such a spike, but I assume it has to happen. Each time I actually test the alkalinity with my Red Sea test, it is always 9.8-10.1 dKH but that is just a snap shot.

I add almost no supplemental calcium with my dosing pump, and I add no other alkalinity (i.e., carbonate/bicarbonate).

I've heard of some people dripping limewater instead of utilizing it as ATO. How do you guys dose limewater? Do you have to refill your limewater doser each day?

I totally admit I don't have any data to prove alkalinity swings. I just have observation and logical deduction.

Randy Holmes-Farley · Oct 18, 2017

You can use a dosing pump, but it's easy to estimate what "spike" you might get if you know how much volume your ATO deliver with each triggered delivery. It is likely small.

AllSignsPointToFish · Oct 18, 2017

It's about a gallon of water each time the topoff actuates. I would assume that the ATO water is a saturated calcium hydroxide solution as I actually add a little more than one teaspoon per gallon.

I would estimate that I add about 1.25 teaspoons of calcium hydroxide per gallon of DI water.

Randy Holmes-Farley · Oct 18, 2017

A gallon each time? What size tank are we talking about and how many total gallons replaced by the ATO per day?

AllSignsPointToFish · Oct 18, 2017

Yes, the total system volume is around 125 gallons. It takes about 3 quarts to fill the sump between the ATO low and high level probes, and the ATO usually runs 1-2 times per day. I don't have a chiller, so I run a fan in the sump to keep the temperature around 77°F.

bif24701 · Oct 20, 2017

I have my pump on a timed program. Turns on for a set time every 1/2 hour. This evens out the additions. I have not observed any fluctuation in water level or salinity after I found the correct time to run the pump. It averages out, 4 min is my time and it's added every 1/2 without fail. You can roughly calculate the time needed and adjust it from there. Won't take more than a couple days and it's much safer IMO.

Randy Holmes-Farley · Oct 20, 2017

AllSignsPointToFish said:
Yes, the total system volume is around 125 gallons. It takes about 3 quarts to fill the sump between the ATO low and high level probes, and the ATO usually runs 1-2 times per day. I don't have a chiller, so I run a fan in the sump to keep the temperature around 77°F.

IMO, that is too fast unless it is a very slow pump. I'd look to use a very slow pump to spread out that dose.

AllSignsPointToFish · Oct 20, 2017

I'm already using the smallest pump I can find, and I have a zip tie around the silicone tubing to restrict the flow. The ATO unit I use has a 10 minute time-out, so the pump I choose can't be too slow.

Orm Embar · Oct 21, 2017

I use Bulk Reef Supply's DIY kalk dripper, with an IV set (roller clamp) to fine tune how fast it drips. The other option would be a dosing pump, which would be more expensive but more precise. As it turns out, the dripper is working well so far. I stopped putting kalk in the ATO simply because the precipitate would clog up the tubing occasionally (and for more consistent kalk addition rates that aren't influenced by evaporation)

zsuzsu · Oct 21, 2017

AllSignsPointToFish said:
I'm already using the smallest pump I can find, and I have a zip tie around the silicone tubing to restrict the flow. The ATO unit I use has a 10 minute time-out, so the pump I choose can't be too slow.

get a tunze osmolater, mine comes on countless times per day, i think its time out is about 2 mins. it also has a max amount limiter so you really can't flood your system. imo its the only ato to use.

zsuzsu · Oct 21, 2017

Orm Embar said:
I use Bulk Reef Supply's DIY kalk dripper, with an IV set (roller clamp) to fine tune how fast it drips. The other option would be a dosing pump, which would be more expensive but more precise. As it turns out, the dripper is working well so far. I stopped putting kalk in the ATO simply because the precipitate would clog up the tubing occasionally (and for more consistent kalk addition rates that aren't influenced by evaporation)

i get around the kalk destroying ato pump thing this way.... i mix my kalk in a 5 gal. pail, let it sit overnight, then i siphon off only the clear water above the crap on the bottom of the mix pail into my ato tank (my siphon hose is just a combination of rigid and flexible air tubing) this way i get the benefit of using kalk and only clean my pump twice per year. good luck n stuff...... zsu

Randy Holmes-Farley · Oct 21, 2017

AllSignsPointToFish said:
I'm already using the smallest pump I can find, and I have a zip tie around the silicone tubing to restrict the flow. The ATO unit I use has a 10 minute time-out, so the pump I choose can't be too slow.

One can use dosing pumps which are much slower. I used a Reef Filler diaphragm pump which can be set as slow as you want. Peristaltic pumps also work fine.