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Discussion Starter · #1 ·
Hello,

Over the past 2 weeks I have noticed my calcium has dropped to 300.

Alk is at 7.9
PH swings from 8.1-8-45.

I have been trying to raise the calcium with kalk. 1 1/2 tsp pre gallon.

Calcium has barely increased it is now at 310.

Tank is a 58.

Also, I guess I can add more kalk for my top off water but I evaporate 2 gallons a day now that my auto topfoff refills twice a day when needed.

Trying to match the drip rate with teh evaporation rate is a pain (dont know how to keep it matched).

Any ideas? The PH is climbing as well.
 

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Hi Rob, some basic info first.

What is your salinity and how are you testing it? How and when are you testing for your pH? Which kits are you testing your Ca and alk with?

As far as matching your drip rate minute for minute, I wouldn't worry so much about that right now unless you want to keep some salinity-sensitive creatures like Linckia spp. starfish. Although for your specimens to really thrive they almost always do best with full strength seawater at a constant salinity, for now you can get by with the following procedure until you can afford something better.

Calculate your exact replacement over a 24 hour period. The best way to do this is to mark your sump's water level (or tank level if you don't use a sump) with a piece of tape and write the time on it. Come back in 24 hours and refill your sump to that exact level. Record the amount of top-off that you use to do this. Do this every day for a week and determine precisely what your top-off is based on a 7 day average. Be careful to not add any seawater from new acquisitions, account for skimmate volume, etc. Check your salinity at the beginning and the end of this time period to account for any salt losses (usually creep or skimmate or specimen removal from the tank). Once you have determined your systems AVERAGE DAILY EVAPORATION rate, you can drip that much Kalkwasser into the tank every day over several hours. It doesn't have to take 24 hours, although that would be ideal. Simply run your drip rate at such a rate that you deliver your kalk within the 24 hour period, whether it be 7 hours or 23.5 hrs. Make sure to replenish your top off dose every day. I am sure that you know this, but never dump in large volumes of Kalkwasser directly into the tank at one time, it is important for the lives of your specimens that it take several hours.

Once you have the funds available, either buy or build a top off system using a Kalkreactor and a reef-filler pump or refurbished IV infusion pump. Most pumps need to have the minimum hourly capacity to deliver at least your daily evaporative losses. If your tank evaporates 3 gallons US a day, that is approx 4000ml/gal x 3 gal = 12000ml/day, and to deliver 12L (12000ml) your pump must be capable of delivering 500ml/hr. There are plenty of sites that have plans for the dyi Kalk (Nielssen) reactors, basically they allow you to mix a large amount of dry Calcium Hydroxide in a large vertical column of seawater that is stirred by either a magnetic stirbar or a recirculating pump dedicated to 4 to 6 times a day recirculation of the contents of the container (to maintain saturation). The infusion pump feeds water into the reactor, and the displaced volume from the kalk reactor is fed into the sump. You simply keep the fresh RO/DI reservoir filled and replenish the Kalk powder every month or so. It does require that you maintain a watch on the salinity of the tank on a regular (weekly) basis to make sure that your evap rate hasn't changed. Many folks dial their kalk infusion in at 80 to 90% of their total evap rate and use an auto top-off float switch setup with fresh water to make up the difference.

This is my personal preferred method for Ca and alk supplementation for several reasons, although in highly hermatypic autotrophic systems the Ca requirements may not be matched by Kalk alone and may require a CO2-based Calcium reactor to make up the difference.

HTH, anxiously awaiting your answers...:D
 

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Discussion Starter · #3 ·
Salinity is 1.025 using a refractometer.

I am dripping kalk as well as adding automated fresh topoff using a floatswitch on a timer twice a day as needed.

I dont dump the kalk in at once.

Over the past 2 weeks I go through a gallon of kalk mixed water plus fresh water from the auto topoff.

A kalk reactor would require a reef filler type pump. My concern with that is say the tank doesn't need topping off the reef filler will continue to dump water into the sump causing a flood.

The PH is starting to rise is this due to the kalk?
 

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Rob_Reef_Keeper said:
Salinity is 1.025 using a refractometer.
The salinity is good enough based on your SG of 1.025 (assuming 80F temp). In some tank systems, low salinity is the only cause of low Ca and Alkalinity. If you are shooting for 400 PPM Ca and 11 to 13 alk, bump your salinity up to 35 PPT.

I
Rob_Reef_Keeper said:
...dripping kalk as well as adding automated fresh topoff using a floatswitch on a timer twice a day as needed.
for your system now, replace all the evaporative losses with saturated Kalkwasser solution. I might suggest mixing 2 tsp. per gal of RO/DI water, agitate WELL for about 5 min., allow to stand for 30 min to 1 hour (closed container) and drip in your total replacement volume over 6 to 8 hours.

Rob_Reef_Keeper said:
A kalk reactor would require a reef filler type pump. My concern with that is say the tank doesn't need topping off the reef filler will continue to dump water into the sump causing a flood.
This is why you need to take a 7 day running average based on refilling every day at exactly the same time each day. Run the infusion pump at 80 to 90% of the total daily AVERAGE consumption, and use an auto topp-off device to make up any extra need in evaporative losses. If you'll do this as in the original part of the response, it will run without problems. I have a system that has used such a method for around 5 or 6 years with NO problems. If you are truly concerned, get a float switch for your sump and set it up to cut the power to both the auto top-off powerhead and the reef filler/infusion pump when the water level reaches a certain maximum level.

Rob_Reef_Keeper said:
The PH is starting to rise is this due to the kalk?
The pH of your system w8ill marginally rise with the addition of kalk, but the pKa of the resulting CaCO3 and carbonate/bicarbonate zwitterion pair arrangement will not go above 8.3, more like 8.2. The actual pH of your system will run from a daily am low of 7.05 to a nightly high of 8.4 to 8.6, depending on many variables within your system. The time of day, the methodology of testing, the test kit used Vs meter variables for the sample, and where you pull your sample from in the tank will determine what the pH of the sample will be. You will need to be more specific on your pH question and give us the necessary details for the pH answer, although there are a few threads in the archives that may answer this for you. If you use a meter and you've seen a gradual climb in the pH at the same time every day, most meters do this as the battery gives out.

Sorry to not be more specific on the pH part, but you need to supply more information to get a more specific answer.

HTH
 

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Discussion Starter · #5 ·
thanks.

PH is via a Pipoint PH meter. It is 8.1 in the morning and 8.45 at night when the lights just go off.
 

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Rob_Reef_Keeper said:
PH is via a Pinpoint PH meter.
The pH range looks fine to me, this is a normal range for closed marine systems. Just as an aside, if there have been changes in your meter readings but not in your husbandry regimen, you might want to do some of the meter maintenance in this thread

HTH
 

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Discussion Starter · #7 ·
Another?

Tank goal is to have an SPS and clam enviroment.

Comparing a calcium reactor to a Nilsen reactor.

Nilsen will cost a few pennies plus the Reef filler.

A small calcium reactor for my tank might be similar price, no? Which is better?
 

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Rob_Reef_Keeper said:
...goal is to have an SPS and clam enviroment... ...Comparing a calcium reactor to a Nilsen reactor...Which is better?
A lot of this will be determined by how much maintenance you want to perform and your personal preference for the technology.

A good CO2 based Ca reactor will run you somewhere in the vicinity of $350 to $450 US IN THE US...:eek: This with an additional expense on purchasing a $100 CO2 cylinder and keeping it filled at anywhere from $30 to $50 depending on tank size and where you have it filled. This compressed air tank has the potential of being a rocket if it is accidentally knocked over and the valve is knocked off, although I am sure that most folks can take precautions to prevent this. The CO2 based reactor is one of the best methods of supplying Ca and Alk once it is dialed in and operating correctly, although this becomes one of the issues of operation, especially with the lower quality non-needle regulators. As adjustment drifts, excess CO2 enters the processed water and may result in excess CO2 entering tank water, where it will cause chronic low pH issues. Accumulation of CO2 under the tank stand of many enclosed sumps may also be a problem, as the excess CO2 is trapped under the tank, artificially raising the CO2 content of the atmosphere that sump water is exposed to, also driving up system pH. Many other issues, if you check some of the threads in the archives on "pH low" or "pH problems", you will find some of them listed as parts of the responses to threads there.

Neilssen reactors on the other hand have none of these drawbacks, they utilize CO2 in the atmosphere of your home/location of the system to supply alk in a reaction with CaO/CaOH. They are easy to make, relatively inexpensive, for most systems there are refurbished IV infusion pumps that will handle the infusion rates needed (usually $75 to 100 US), and cheap to operate (Mrs. Wages pickling lime is about $1.49 a pound last I checked :D ). I have experimented with systems where the float switch pushes the kalkwasser as a small bolus into a container that is floated in the sump with a diffusion grating. This allows a cheap float switch to operate the top-off through the reactor, and the diffusion apparatus allows the kalkwasser to slowly be displaced into the sump by incoming water to prevent large doses of Kalk at one time. Still working out a few bugs on this, but it bypasses the cost of the infusion pump. I would personally prefer that you use a pump that you can dial in your dose, as it will tell you exactly how much your corals are consuming based on the numbers that come back from your Water column testing.

There is an additional benefit to Kalkwasser reactors in that they pretty much precipitate the phosphate out at aquaria pH when kalk is added to the water column, and most of this can be skimmed out of the water column by the skimmer. In the pH range of 7.9 and up, Ca Phosphate is almost totally insoluble, and it is finely divided enough at the point of precipitation to stay in suspension for several cycles through the tank, plenty of time for the skimmer to remove it as part of the suspended materials it takes from the water column.

BTW, I can tell when the kalk needs to be replaced by the am pH shifting down to 8.0 or less as the kalk is consumed from the reactor.

JMO, HTH
 

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Discussion Starter · #9 ·
Thanks for the help.

Now to find a cheap pump. And some clear acrylic for theNilsen reactor? Do I have to use clear acrylic for the reactor?

All the DIY sites show theirs with acrylic tubing.
 

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Rob_Reef_Keeper said:
Now to find a cheap pump. And some clear acrylic for theNilsen reactor? Do I have to use clear acrylic for the reactor?.
You can, but the only part you really need to have clear is the reaction chamber at the bottom to tell both when you are out of kalk and if the reactor needs cleaning. Use the smallest Maxijet for the pump, it works great, and you can plug the cord into oneof those multievent timers to have it mix the kalk 4 or more times a day, just needs to turn on and off for about 3 minutes four times a day
 
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