cheap automatic dosing of calcium hydroxide (kalkwasser)

[mehdirah]

Hello,

just to signal the system I devised for my two 300 l reef aquariums. I was begin to be fed up with preparing and adding kalwasser every day and didn't wantes to invest into a calcium reactor with a water height detector (very expensive and I don't have a sump, so no good place to put the detector)

So, I did the following system for each aquarium. I bought an AQUASTAR - VARIO 1 PRO peristaltic pump. This is by far the cheapest peristaltic pump that I found on internet (93 euros on http://www.seame.com/nl).
They said the flow rate is 38 ml/min, but I measured 50.

Of course, this is far too fast to add calcium hydroxide, so I combined it with an electronic circuit to activate it for about 1s (which is what I need to compensate evaporation) with a pause of 30s, running 24h a day. This give me a ph of about 8.4 before HQI go off, 8.1 on morning just before the HQI starts.

I could have designed the control circuit myself (I saw similar circuits to control powerhead pumps, the correct name is interval timer and is based on a ne555 chip), but I found easier to buy a kit with all electronic components and the printed circuit: the MK111 from velleman (www.velleman.be). It costs 7.5 euros and allow to change the pause time up to 30 s (they said 1 minute, but it is not true) and the on time up to 5 seconds. This circuit is also very pratical as it needs 12V DC as alimentation, which is also the one of the pump... this simplify the mounting.

The last part was a plastic box with an hermetical cover, which can really contain 60 l of water and in which I prepared the solution. As it is hermetical (just one small opening for the tube which goes to the pump and one to fill with RO water), the solution does not deteriorate. So, I just have to fill it every few weeks.... and forget the system the rest of the time.

It is a pleasure now to do not have to check water level, prepare solution... and explain to my neighbour how to do when I go in vacation for a few weeks.

 

[Anonymous]

I played with the 555 IC since I was a little kid. It and its brother (ne556) can be very useful when it comes to little gadget like a timer. Velleman kit is also nice, but they are not readily available (only a few distributor in the USA). But it is nice to get a kit and just have to solder things together and expect it to work.

Glad for the pointers and comment.

I just want to comment on that a calcium reactor does not use height detector (aka top off switch). It runs continuously. A kalkwasser reactor, OTOH, does need a top off switch. Did you confused these two reactors together?

 

[mehdirah]

Maybe I confused a bit the name in english

I was speaking of the system which add a solution of calcium hydoxyde in the aquarium.

 

[Anonymous]

Alright. So why did you only look into kalkwasser reactor, and not the calcium reactor? BTW, you can also get the kalkwasser reactor to work with a peris. pump like your setup...

 

[mehdirah]

Hello,

simply because my aquariums are far from being full of corals (just one acropora and one tridacna clam in one, nothing yet in the other), altough this will surely change with time . So kalkwasser was, from my point of view, more than enough. It also has the advantage to maintain a high PH, which helps to block phosphates and thus algae growth (my last few filamentous algae disappeared when I began to add kalkwasser manually a few months ago).

I will add a calcium reactor when the aquariums really need it. I am a bit afraid of the CO2 dosing, which can lead to PH drop and hairy algae if too much is given, and to clogging of the reactor substrate. Kalkwasser reactor seemed simpler to me.

When I will have to add a calcium reactor, it will probably be in addition to my actual system, as one tends to increase PH and remove CO2, while the other do exactly the opposite.

 

[Anonymous]

If done properly, the pH drop often associated with the use of ca rxtor can be elimitated if the output is put in a high flow area. Same thing for kalk dosing and kalk rxtor. If the output is not drip in a high flow area, the ca hydroxide will come out of the solution too quickly and the desired effect not archieved optimally.

In addition, the misconception that CO2 of ca rxtor will increase hair algae is not true. In saltwater tank, the CO2 is not the growth issue for algae, while CO2 dosing is often desired in planted freshwater tank to enable the high density of plant in the tank. Knowledge from one system (FW) does not necessarily applies to the other (SW).

IME, ca rxtor substrate rarely clogged if the substrate is changed periodically (a couple times a year).

I am not trying to convince you to use ca rxtor, since you understand the pros and cons of numerous Ca dosing methods pretty well. I just want to point out some of the misconception and myths related to them, and offer a point of view that different from other. The comments are nothing but my opinion and 2 cents worth.

 

[mehdirah]

Thank you for the additional info about calcium reactor. From your comment, I see that it is simpler to manage that what I previously tought, so may be my next DIY toy.

 

[MLVA123]

I've read that putting the kalk into the skimmer is a desirable thing to allow the skimmer to yank out any of the ca coming out of solution before introduction into the tank. That seems to match with your comment David about putting the kalk into a high flow area. Any opinions on this method?

 

[Anonymous]

Skimmer input is a good place for dosing kalk, if the skimmer is designed for it and the kalk reactor has enough pressure to push the output thru the skimmer. In addition to what you realized, it also alleviate with the pH swing issue since the gas exchange inside will neutralize the base. However, there is a possibility that this may cause a higher than usual precipation of calcium prematurely, but I did not look much into it other than just a conjecture right now. AFAIK, there is no advantage or disadvantage in putting out the precipated calcium out of the water right away.