Lessons Learned From Kalk Disaster

[Rascal]

OK, so I don't give up easy. After recently nuking my tank with a Kalk overdose, I am back at it. I have come up with the following solutions to avoid a repeat of the problem. Let me know what you think.

 

First, a little background. Primary Ca & Alk supplementation is accomplished with a Ca Reactor. I use Kalk mostly as a means of maintaining Ph. My top-off reservoir sits about 15 feet from my sump. Top off is controlled via solenoid float switch which turns on a MJ600 sitting in the top-off reservoir. This is connected to 1/2" and then 1/4" tubing which feeds a Kalk reactor. The Kalk reactor hangs on the side of the sump with it's output suspended a good 10" from the water level, so no back siphoning is possible. The feed into the kalk reactor run through a T fitting which prevents back siphoning from the reactor to the top off reservoir. Flow into the kalk reactor is controlled with a pinch valve on the 1/4" tubing, so that when the top-off pump comes on the water leaves the reactor in a slow but steady drip. This method of controlling the flow worked without flaw for about 2 years as long as I just leave it alone and don't mess with it. Inside the reactor is a new MJ400 suspended a few inches from the bottom with it's output oriented down - pointing towards the 1 cup of kalk on the bottom of the reactor. It is dialed down enough so that when it comes on it stirs up the kalk but not enough to make the liquid all the way at the top of the reactor turn white.

 

My ACIII programming:

First the Ca Reactor

If Ph < 8.0 then CO2 OFF

If Ph > 8.1 then CO2 ON

This turns on and off the solenoid and recirc pump if the tank PH drops too low. The feed pump turns on. I don't monitor the internal Ph of the reactor, I just measure the results and adjust when needed - which is not often.

Now the Kalk / Top-Off

If Ph < 8.3 then KAL ON

If Ph > 8.35 then KAL OFF

OSC 001/059 ON/OFF THEN KAL ON

When Ph is less than 8.3 the mixing pump turns on for 1 min every hour. When Ph rises above 8.35 the mixing pump shuts off completely.

 

In the 2 weeks I have had it set up this way, Ph has held steady b/n 8.26-8.36 for the most part, with a low of 8.21 and a high of 8.39, so it is accomplishing what I want (target Ph of 8.3) but my concern is what can/will go wrong.

 

I am thinking of adding a second solenoid switch and back-up top-off pump which will by-pass the kalk reactor entirely, and then using the ACIII to switch to the by-pass as soon as Ph gets over 8.4.

 

Any thoughts?

[WDLV]

OK, so I don't give up easy. After recently nuking my tank with a Kalk overdose, I am back at it. I have come up with the following solutions to avoid a repeat of the problem. Let me know what you think.

 

First, a little background. Primary Ca & Alk supplementation is accomplished with a Ca Reactor. I use Kalk mostly as a means of maintaining Ph. My top-off reservoir sits about 15 feet from my sump. Top off is controlled via solenoid float switch which turns on a MJ600 sitting in the top-off reservoir. This is connected to 1/2" and then 1/4" tubing which feeds a Kalk reactor. The Kalk reactor hangs on the side of the sump with it's output suspended a good 10" from the water level, so no back siphoning is possible. The feed into the kalk reactor run through a T fitting which prevents back siphoning from the reactor to the top off reservoir. Flow into the kalk reactor is controlled with a pinch valve on the 1/4" tubing, so that when the top-off pump comes on the water leaves the reactor in a slow but steady drip. This method of controlling the flow worked without flaw for about 2 years as long as I just leave it alone and don't mess with it. Inside the reactor is a new MJ400 suspended a few inches from the bottom with it's output oriented down - pointing towards the 1 cup of kalk on the bottom of the reactor. It is dialed down enough so that when it comes on it stirs up the kalk but not enough to make the liquid all the way at the top of the reactor turn white.

 

My ACIII programming:

First the Ca Reactor

If Ph < 8.0 then CO2 OFF

If Ph > 8.1 then CO2 ON

This turns on and off the solenoid and recirc pump if the tank PH drops too low. The feed pump turns on. I don't monitor the internal Ph of the reactor, I just measure the results and adjust when needed - which is not often.

Now the Kalk / Top-Off

If Ph < 8.3 then KAL ON

If Ph > 8.35 then KAL OFF

OSC 001/059 ON/OFF THEN KAL ON

When Ph is less than 8.3 the mixing pump turns on for 1 min every hour. When Ph rises above 8.35 the mixing pump shuts off completely.

 

In the 2 weeks I have had it set up this way, Ph has held steady b/n 8.26-8.36 for the most part, with a low of 8.21 and a high of 8.39, so it is accomplishing what I want (target Ph of 8.3) but my concern is what can/will go wrong.

 

I am thinking of adding a second solenoid switch and back-up top-off pump which will by-pass the kalk reactor entirely, and then using the ACIII to switch to the by-pass as soon as Ph gets over 8.4.

 

Any thoughts?

 

This is kind of a broad statement but it does cover the gist of what you're asking.

 

I've been reefing for about 11 years and been working with medical electronics, pneumatics, hydraulics and robotics for about eight. What I have learned is:

- Redundancy can save your butt. Don't have one circulation pump, one light timer, one closed loop etc. Get two or more. That $20,000 worth of prized fish and coral can be wiped out in a matter of hours from a full sized heater that got stuck in the on position. More often than not, they fail "ON." If one of three smaller heaters fails on, you have time to catch it.

- Use float valves instead of float switches. Solenoids get dirty and leak and electrical contacts get dirty with carbon and fail over time. Float valves usually fail by not providing water. Which to me is far preferable. It's the difference between saying "gee, the sump level looks low" and saying OMG, what happened!"

- Do not use a method of kalk dosing or top off that would allow a free flow in your tank if there were a sump leak. (I use a LiterMeterIII.) Paristaltic pumps usually fail when the tubing fails. In which case they stop providing kalk to your system.

- Don't put all your eggs in one basket. IE: i think aqua controllers have their place but I do not believe that aqua controllers are the way to go for every feature of your system. Control each device or at the least, every system individually. It might cost more but you're far less likely to come home from vacation with a glass box full of rotting sludge. If a timer fails on one of your lights, your corals will probably bleach in that section of the tank, but if the aquacontroller that controls your pH, top off, lights, heaters chiller, pumps, Ca Reactor and your whatchamagiggy fails, what happens then? You'd better hope grandma or whomever is watching your house notices fast and knows what to do about it.

 

Essentially, "the more complex the system, the more likely it is to fail" don't put all your eggs in one basket and remember that "Murphy" is not your friend. Don't tempt her.

Edited October 28, 2008 by WDLV