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Discussion Starter · #1 ·
When I first set up a calcium reactor several years ago, I read that the best way to tune them was by testing the effluent pH. I got that advice from articles like the following:

http://www.reefkeeping.com/issues/2002-05/sh/feature/index.php


But, after almost overdosing my tank (alk shot up from 8 to 12 in about two days), I began to wonder why I was tuning based on pH. Shouldn't I be tuning the reactor based on effluent alk? After all, my demand is in meq/liter/day, shouldn't I focus on adding the same amount of meq/liter/day.

I now run my reactors with effluent pH of around 7.0 - 7.2 (at least that's where it was the last time I checked).

Why is the standard advice to run pH in the mid and upper 6s, when pH in the low 7s works just fine, and why measure pH at all, when what matters is replacing alkalinity with alkalinity?
 

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Discussion Starter · #3 ·
Spanky said:
Shouldn't pH be tired into dwell time?.
pH should be based on CO2 concentration (all other things being equal). Higher ppm CO2, the lower the pH.

Spanky said:
I mean if you're shooting a lot of water through it and adding a lot of CO2, that wouldn't be the same as slow flow and longer dwell.
There’s the rub. Both scenarios may show the same pH, but the first one (lots of water and lots of CO2) will add much more alkalinity to your tank. That’s why I believe there is a significant risk of overdose if you just focus on pH.
 

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I don't focus on either. :)
I count bubbles, watch the drip rate and then check the tank's Alkalinity, not the effluent.
After all, the tank Alk is the parameter that matters, isn't it? If my effluent is 18 DKh, what do I care? That tells me nothing about what's going on in the tank. That's assuming you aren't depressing the tank's pH too much. With a dual chamber reactor, I've never noticed any significant pH drop with or without the reactor online.

I never understood why people want flow meters, pH monitoring and effluent monitoring when none of it equals optimal tank Alkalinity. :confused: Maybe I'm just old-fashioned. :) Or stoopid.
 

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Well when I was driving today, It hit me, I think we all got off track some where, I test for Alkalinity as a final result, but in the process I also have a controller to operate my CO2, I like to keep the PH in the first chamber 6.6 to 69. in that range, sometimes it may go to 7.0, But not lower then 6.6. I also think by having a controller it is easier to control and have stable level and save on CO2, You slow the output of the reactor down and hold the 1stchamber at that lower ph and break down the media at a constant rate. Which in turn gives a more stable alk.
By not having a controller and just counting the bubbles , I would think You may never really get the ph to a level to work on the media to break it Down, JMO on this. I am no expert. You will be moving water at a much too fast of rate and using more CO2 and have more of a chance of having excess co2 enter the tank.
I know it may work for You but I also think reading the ph and having a controller and operating it in this manner is also a very effective way to operate You reactor. JMO again

Also I am more concern with Alk then Calcium when it comes to readings, I don't do allot of testing as I have found my tank to be very stable.
 

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Discussion Starter · #6 ·
Isn’t the idea behind a controller to turn the solenoid off if the pH level gets too low? It would seem to me that you would then have more variability than if you just adjusted the needle valve on your CO2 regulator to a continuous, constant bubble rate.

When the Schuran Jetstreams became very popular, I read a number of posts from people saying their reactor was so wonderfully powerful they could only have the CO2 on for a few hours a day. So, the pH in their reactor was constantly swinging from the mid 6s with the CO2 on to the mid 7’s (or higher) with the CO2 off.

I kept on wondering why they didn’t just turn the CO2 bubble rate down and have it run continuously with a pH of about 7 (or not even focus on the pH at all).
 

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I do it the easy way. 1 bubble every 2 seconds and 1 drip per second. that has worked perfect for me. Does anyone run the reactor on a seperate tank and then dose the effluent seperately? i would think that would help to control what goes into the tank better and protect you if something goes awry.
 

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Monitoring the PH is just a tool. I set my reactor based on bubbles/drips to keep up with the alk demands of my tank. If the flow output or CO2 input changes it is reflected by looking at the PH. If you don't pay attention to all 3 things you are asking for trouble. If you can't handle the fancy gadgets you can always do it the old fashioned way like Spanky.:funny:
 

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I dunno. The next time I do a reef, I'm thinking more along the lines of 2 part with auto-doser. There's a local guy who's been doing it since Randy H-F published his recipes. Swears he'd never use a reactor again.
 

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Reefrubble said:
If you do two part,how do you go on a vacation?
Mix up 5 gallons of each part, dosed by a 2-channel auto-doser. Could probably get by with only a gallon or two actually - depending on need.
Probably less maintenance than a reactor, really - and about as much or even less "tune-in-time".

The dosers aren't cheap, but they are cheaper than reactors these days - especially if you don't already have the CO2 system.
 

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Graham said:
Mix up 5 gallons of each part, dosed by a 2-channel auto-doser. Could probably get by with only a gallon or two actually - depending on need.
Probably less maintenance than a reactor, really - and about as much or even less "tune-in-time".

The dosers aren't cheap, but they are cheaper than reactors these days - especially if you don't already have the CO2 system.
You know I just bought a big fancy reactor, but I am thinking of doing just that.
 

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A few guys down here have done just that. You can tune 2 part in two days. As opposed several days or weeks with reactors.

You can figure out exactly how much alk is consumed in a day, and then you can calculate exactly how much 2 part to dose every day.
 

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I don't focus on either.

I count bubbles, watch the drip rate and then check the tank's Alkalinity, not the effluent.
After all, the tank Alk is the parameter that matters, isn't it?
That's how I do it also. It was the easiest way for me. I measured my ph effluent just for fyi & it was around 7-7.1. The only thing I care about is that the reactor is stable & keeps up with the usage.

I've never had to worry about my tank ph getting dangerously low either.
 

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You can figure out exactly how much alk is consumed in a day, and then you can calculate exactly how much 2 part to dose every day.
Can you explain this further? I know you can figure out how much is consumed, but how do you calculate how much of each two part to use?
How is this done mathematically?

I think my Litermeter with two pumps would be a lot more reliable than a reactor. Plus I'm not adding that extra phosphate from the reactor media.

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EdFink said:
Can you explain this further? I know you can figure out how much is consumed, but how do you calculate how much of each two part to use?
How is this done mathematically?

I think my Litermeter with two pumps would be a lot more reliable than a reactor. Plus I'm not adding that extra phosphate from the reactor media.

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Consumption is straight foward, measure one day and record, measure the next day and record, subtract and you get daily usage.

Then to get how many mL to add per day is a matter of some straight forward calculations based on tank volume, and concentration of your stock solutions of two part.

Perhaps the easiest way if you are using Randy's standard solutions, is to use the calculator here:

http://reef.diesyst.com/

For current alk put it the reading from day two, for desired alk put in the reading from day one (or any combination of values with a difference equal to the daily consumption rate you've calculated)

Then pick a product, either from the list, and hit Submit alk. It will tell you exactly how many mL's you need to add daily, and then you can set the LitreMeter up to add that much every day.

Set and forget.

If you want the maths I can run through that if you want, but the calc's faster and easier.

Layton
 
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