Automating Two-part Dosing With a Litermeter 3

So, you got a LM3 - great choice! Automating certain tasks in your daily aquarium maintenance routine can be a very relieving experience - Two-part dosing is no exception. Not only can you relax a bit, but it is a great benefit to the health of your tank inhabitants - your stony corals will love the stability of calcium and alkalinity levels that automated dosing provides, and you can take comfort in the fact that you no longer have to fill those dinky little cups and remember to add them to your reef tank once or twice a day. There are a few different dosers (peristalic pumps) of various quality & pricing on the market but let’s take a look at the only one (that’s readily available in the US) worth anything (my opinion only)…

The Litermeter 3 comes as a single unit with a dosing pump attached to the main control box. With this single pump, many use the LM3 for topping off RO or Kalkwasser. In order to dose two part solution with the LM3, an additional ‘remote pump’ is required. I personally use the LM3 and 2 remote pumps to satisfy my RO/DI top-off, as well as my daily dosing of 2part. It’s a no-brainer. All I have to do is refill my calcium and alkalinity two-part containers once every 20 days, and keep the RO/DI filled as need be.

One of the beauties of the Litermeter 3 is that it doesn’t dose the given product just once a day and that’s that - it continually doses 150 times over the course of 24 hours. By doing this, your product, be it Ca or Alk supplement is always present - as some is used up by the animals, a bit more is going in. This is also a kind of safety - making it difficult to overdose. Sure, if the daily amount you set or the mix ratio (getting to that in a moment) is an overdose in and of itself and you don’t check your tank, you can OD. But, if the LM3 is set properly and your ratio is correct, you can sit back and enjoy a stable tank.

If you are switching to two-part solution from something else, a Calcium or Kalk reactor, or whatever, you’re going to need to go thorough the steps, testing daily, observing consumption, etc. We’re going to assume that you have already been dosing a 2 part solution, and you know the amounts you need to dose on a daily basis. We’re also going to assume you’ve gone through the manual of the LM3 and have calibrated all pumps properly.

To set up the Litermeter III for automated calcium and alkalinity dosing, you need 1 main unit, and 1 remote pump, as well as 2 nice containers for holding the solutions. I rigged a couple these 99 cent jugs from KMart using John Guest compression fittings so they’re sealed, and easy to remove from the LM3 to refill - they’re great because they have markings in mL and Oz. on the side already.

To determine the ratio of solution to RO/DI in the containers, the first step I recommend is thinking about how many days you want to go without thinking about it! My setup is adjusted so I only refill every 20 days. I choose 20 days for 2 reasons - 1) that is about how often I like to check my Magnesium levels (Mg is a very important part in keeping a balanced aqaurium) and 2) that is about the least amount I can accurately dose with the LM3.You next need to know how much total solution (mix of the Ca or kH additive) the containers you

So, let’s use my set up for example. I make 20 days worth of solution, and my containers hold 2000 mL. To figure the setting you need on the litermeter LM3 it’s simple, divide the total solution volume by the number of days - 2000 / 20 = 100. Since the units I used are milliliters (2000ml volume in container), and the LM3 display is in Liters, just convert ml to liters, so 100 ml = 0.10 L. That’s the setting for the “flow rate” on the front of your LM3! Please note, the Lm3, according to Scott at Spectrapure *may not* dose less than 50ml / day accurately. He said it may, but they say 100 or 150 min in the manual.

Now, unless you have a huge tank and are dosing 100’s of ml of two part solution daily (I’d definitely consider a reactor!), you’re going to need to dilute. As mentioned, we’re going to assume you know the daily amount of each part of the Ca/Alk solution. For the sake of brevity and ease of math, let’s say you know you need 10ml of each per day. Since we chose 20 days, multiply 20×10 = 200 - you need to add 200ml of the actual Ca/Alk solution to your container. From there, fill the remaining (since we chose 2000ml container) 1800ml with RO/DI water - and start dosing!.

Be sure to check your levels weekly. If you see kH dropping or going too high, there are a couple options. When I see Ca or Alk dropping, I do not mess with the LM3 at all. I simply use JDiecks’ Reef chemisty calulator to figure out the amount I need to bump it up, and add it by hand. This way, you don’t have to get into messing with your established settings or mix ratio. If the levels getting too high, just turn that specific pump off and test 24 hours later. I’ve found that my ratio of solution:RO/DI doesn’t really change - I get occasional spikes or drops, but overall, I’ve had the same mix for ages.

So to sum up the formula:



#3) ADD RESULT FROM #2 to container and fill the rest with RO/DI.

Any questions on the formula or suggestions for other ways, please feel free to mention below. If you  need help calculating for your tank, give a holler as well, just give the details in a comment below and I’m happy to try and help out. Congrats on your purchase!