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Thread: Noob Questions - DOS rate etc.

  1. #1
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    Noob Questions - DOS rate etc.

    I got my Apex with DOS yesterday. I have it mostly set up now.

    I have a few (probably easy) questions for more experienced people out there.

    I want to dose BRS two part into my basement sump. My display tank and sump total about 220 gallons.

    My Alkalinity is currently at 7.6 dkH. My calcium is at 380 ppm.

    According to the BRS calculator I need to use 140mL of their alkalinity solution and 901mL of their calcium solution to raise my values to 8.5 dkH and 420 ppm respectively. I am new to dosing so before I kill something I wanted to make sure these numbers pass the "reasonable-ness" test. Comments appreciated.

    So now on to the DOS questions:

    1) The DOS appears to work on a 24 hour schedule. I set up pump one (alkalinity) to run from 0700 to 1200. I set pump two (calcium) to run from 1200 to 2359. Does this sound about right?

    2) Since I think the amounts are fairly large will the DOS try to do the entire amount in one interval or will it do some portion on day 1 and do more on day 2 etc.?

    3) I assume that the intervals I set up in Apex run every day moving forward through time, right? So I will need to modify this set-up once I get my values up to the desired values so that the dosing amount holds them steady, right?

    4) When I create an interval of say 1200 to 2359, and the current time is say 1400, will the DOS start immediately or does it wait until the next scheduled interval to start?

    5. When I was calibrating the pumps I had to prime them. Now that they are set up, do I prime them? I assume that once primed they will hold their prime, right?

    Thanks in advance for any thoughts, opinions and guidance.

    bruce

  2. #2
    Frequent Contributor zombie's Avatar
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    The correct way to determine proper dosing is to use this basic process.

    1. Take a reading of dKH and calcium (denoted below as dKH1 and Ca1)

    2. Wait a specified number of days (denoted below as the variable D) waiting at least a couple with a week being better and make sure it's roughly the same time.

    3. Repeat the reading of dKH and calcium (denoted dKH2 and Ca2)

    4. Enter these values into the dosing calculator for BRS

    (dKH2 - dKH1)/D and (Ca2-Ca1)/D

    This will be your target 24 hour dosing amount. If you need to raise overall dKH then find out the amount to raise 0.5dKH and 50 ppm calcium respectively and add less than that amount into your dosing amount for the required number of days to get your parameter exactly where you want it (also make sure when you do water changes your NSW parameters match these values or the whole thing will be hell to tune)

    5. After parameters are where you want them, stop dosing additional and repeat steps 1-4. Add the value (which can be negative) to your existing daily dosing amount to fine tune. Make sure to wait 1 week or longer on the fine tuning.

    You might be an engineer if...You have no life and can prove it mathematically.

  3. #3
    NSI Member eschulist's Avatar
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    I have no idea on the correct amount that is right for your size tank but I want to help with most of your questions.

    First the raise from 7.6- 8.5 is going to be different than your daily consumption. There is going to be an initial amount you need to add to get your level to your target rate you want to maintain. Check that 140ml and 901ml is an acceptable amount to add in a single day. This could be done through the DOS but after 24 you are going to want to turn this programming off and plug in your day usage amount. Test at the same time 24 hours apart and calculate how much is lost in a single day. You may even want to test over 2-3 days at the same time to find an average per day loss. This is the amount you want to program into the DOS to add every day.

    1. Yes the programming on the DOS is a 24 cycle. Whatever you set will repeat every day on the same schedule. You can choose whatever time frame works best for you. There are a few different opinions and options here. Some people dose their Alkalinity portion at night to raise their pH since thats when it drops and adding alk during that time keeps it elevated. Others dose it during the day when Alk is going to be falling the most. This is shown to be true for many users that run Alk monitors (KH Guardian and upcoming Trident users will see this first hand).

    2. The DOS will split the total amount over the time specified. If you add for example a range from 0000 to 1200 which is 12 hours to add 100ml you can click the gear icon and select Interval summary to see how that is broken up.



    So here it shows that it will dose every 13 minutes 1.8ml of solution. These value and times are calculated automatically and can not be changed. You can do various things to space them out if you need to. For example if you wanted to absolutely make sure both alk and cal were added during the full 24s but never at the same time you could make multiple individual intervals. Alk from 00:00-01:00 Cal from 01:05-02:00 Alk from 02:05-03:00 etc etc. In this scenario you have to manually divide up your amount for the 24 period into the amount of intervals you program in. In my example there would be 12 separate Alk and 12 separate Cal. Each one would need to be your daily value / 12. You can of course make it easier to set up and adjust by using less separate intervals. 00:00-11:55 and 12:05-23:59, having just 1 for each is the simplest as you don't have to do any additional math and division when programming and updating your values in the future.

    3. They cycle every 24 hours. After a few days of the program running you should test at the same time you did previously and see if your values are holding steady. Adjust up or down accordingly.

    4. It should wait until the next interval. In a 12-23:59 with 100+ml of solution it could start within 1-10 minutes.

    5. Once the tubing is completely full of solution it is primed and ready to go. If you calibrated the DOS with standard water to it is primed but the lines have water in them, not Alk or Cal solution. You will have to run the pumps again while attached to your container to push out the old water. Just run them into a separate cup for a few minutes and toss the fluid. You should then be ready to place the lines above your sump / tank and be ready to go.

  4. #4
    Frequent Visitor rkpetersen's Avatar
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    Another approach, one that works successfully for me and others, is to dose both alk and calc evenly over twenty four hours. This results in a mild diurnal pH variation which is not far from what happens in nature. If you have the calc and alk dosing tubes close together, you can separate their dosing temporally by editing the start time of one of the intervals to 5 minutes later than the other.

    I personally wouldn't add all that alk and calc in 24 hours, I'd spread it out over several days, testing as you go, until you get in the right ballpark. Then I'd do the ongoing consumption test as outlined by zombie, and adjust my subsequent dosing based on that. Keep testing, though. Many tanks experience a significant amount of visible or invisible abiotic calcium carbonate precipitation when you try to raise alk and calc quickly, such that your levels don't reach anywhere near what you expect them to be based on calculations. Alk, in particular, often does not rise as much as you would expect. The effect of abiotic precipitation on calcium level is less severe and you may even find that your calcium gets too high while the alk stubbornly stays lower than you want.

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