2 part dosing vs. Reactors

Discussion in 'Water Chemistry' started by tatted4ever, Oct 20, 2009.

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  1. tatted4ever

    tatted4ever Clown Trigger

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    I go thru a gallon of each alk and ca by esv in two months. $35 each time i purchase a set. BRS is significantly less expensive.
     
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  3. Screwtape

    Screwtape Tonozukai Fairy Wrasse

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    If I understand you correctly this is not possible at this time AFAIK. Are you thinking of having CA/Alk/Mag probes that tell the dosers to run when they show the levels are low?

    If that's what you meant than, no. There are very few calcium probes out there and I've heard of some problems with them (pinpoint is the only one that I'm aware of I think), for one they are not designed to be on all the time like a probe they are more like an electronic tester, they also require relatively frequent recalibration. I've heard they can be inaccurate as well, or maybe that just had to do with frequent calibration, I'm not sure.

    There also is not an alkalinity probe that would work either, as far as I understand it alkalinity is pretty complicated, lots of different chemistry that all adds up to a single value we can test with a kit, but there's no reliable way to do that with an electronic probe right now from what I've read.

    As far as comparing long-term costs I read on RC someone recently did some calculations and found out that reactor media was still cheaper than 2 part these days, not by a lot though, at least on their tank which was a 500gal system.
     
  4. ZachB

    ZachB Giant Squid

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    If you are running an Apex you should be able to use the pH as a control to turn outlet off or on (dosing pumps), maybe

    Fallback Off
    Set Off
    If pH > 8.?? then dosing_pump_1 = OFF
    If pH < 8.?? then dosing_pump_1 = ON
    If pH > 8.?? then dosing_pump_2 = OFF
    If pH < 8.?? then dosing_pump_2 = ON

    Or whatever combination you need to use to keep pH regulated at a stable level, 1 being alk and 2 being ca. Maybe my logic is also flawed. Not sure.

    I know you can use pH as a variable, as I have it set to turn on an alarm if it falls under or goes over a certain level.
     
  5. tatted4ever

    tatted4ever Clown Trigger

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    Meaning.... can you have em in correlation to your ph???? isnt that how a reactor runs when wet up with a controller rather than a calcium probe with a pinpoint controller??? I maybe wrong cause I dont know how a reactor fully operates. I know the pure basics of em.
     
  6. ZachB

    ZachB Giant Squid

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    Yes, a CA reactor uses pH. That's why I'm not sure why it can't be done with dosing pumps for 2 part with the Apex. I notice when I dose 2 part my pH spikes temporarily. If you use the pH probe to meter the pH in your tank and then have it dose alk and ca until it goes back up to 8.1, 8.2 etc then shut down, wait for it to fall, dose again, eventually the pH of the tank will actually REACH the desired level and it will simply use the pH probe to turn outlets for peristaltic pumps off and on. If you use a fuge light and reverse photocycle you should notice VERY little change in pH throughout the day, mine hovers around 7.9, then down to 7.8 until I dose and then it goes back up to 7.9 again. The Apex can compensate for pH changes due to temperature flux as well (turn on in your pH setup menu).
     
  7. Powerman

    Powerman Giant Squid

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    That is very expensive. I got the dosing kit with the jugs and all for $70. It will last me for a year. At first I was way overdosing, so I used a lot. I am thinking at the rate I'm going now, a gallon jug will last close to 4 months. After my first small buckets of stuff is gone, I'll buy the bigger 5 gallon buckets and save even more. Should last a couple of years.
     
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  9. Powerman

    Powerman Giant Squid

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    I would not trust this at all!!!!

    One draw back of a reactor seems to be using a PH probe to do things. I have heard of plenty of stories of PH probes messing up with reactors and kalkwasser and over dosing a tank. I do not want to rely on a PH probe for this. One more thing to fail.

    One thing that happened to me..... My house is open all Summer... PH very stable. 8.3-8.35 during the day, and Alk dosing keeps it up to 8.2 at night. Well now it is Winter the house has closed up and my PH has tanked. Thought it was my Alk pump, but it was the additional CO2 in the house. So my ALk pump would have really went off.

    PH is not an indication of Alk. Many things can effect PH and you do not want to be chasing other PH problems with overdosing Alk.

    If you did want to go this route though....... with the APEX, I would use PH to control Alk pump... then give a comand to the Ca pump that when Alk= ON, then Ca = ON. Ya they will be going in together, but the drip rates are so slow it won't matter. Just add them at different points in the sump. At least this way the 2 part will be dosed in equal parts.... CRAP.... that is if the dosing pumps dose equal parts...... Ya.... this is kind of complicated. Dosing times is much easier.
     
  10. Screwtape

    Screwtape Tonozukai Fairy Wrasse

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    If you're just thinking of using PH to control when to dose that's actually not how the calcium reactor works, the PH probe on the reactor is for inside the reactor chamber, you need to maintain a PH somewhere between 6.5 and like 6.9 (if I remember right) for the reactor media to dissolve. The tank's PH is unrelated although a lot of people monitor it in case the calcium reactor lowers the PH too much because of excessive CO2 in the effluent from the reactor.

    Using tank PH to control 2 part dosing is a bad idea, they are not connected directly so you would end up with a disaster sooner rather than later. Just having a few people breathing in the same room with the tank can drop the PH noticably (unless your tank is in an auditorium or something obviously :) ).
     
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  11. wastemanagement

    wastemanagement Eyelash Blennie

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    s/h + currency difference + border taxes It can all add up , not that we pay border taxes on every product/purchase but it happens.

    It sure could be done , but as a few have noted its risky to control with PH probes because after time they can start to fail/missread. I just monitor with my probes

    Damn that makes for an expensive hobbie (105$ for 6mths) 30$ and my CA-media lasts for 6mhts
     
  12. mocarski

    mocarski Bristle Worm

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    +1

    I wouldn't worry much about ph and I would worry about alk. Ph can swing widely without impacting anything in the tank. Alk on the other hand should stay consistent especially if you have sps. Many sps will bleach under relatively small alk swings but not mind wide swings in ph in the least. My ph has swung from 8.3 to 7.7 in a single day without issue.

    The ph controller on a CA reactor is used to control the ph inside the reactor like screwtape stated. When the ph within the reactor goes above a certain ph, the co2 should turn on adding more to the water INSIDE the reactor and lowering the ph. Since the output from the CA reactor is at a slow drip into your system, even if an entire tank of co2 dumps into the reactor, the only thing that should happen is that the media inside the reactor turns to mush and nothing happens to your tank water.

    tatted4ever if your tank is using that much CA, then a CA reactor would be a good investment and would pay for itself fairly quickly.