Arrival!

[Viv]

Here is where I'm at: Ph probe in the reactor is reading 6.79, Ca. dropped to 360, so I supplemented with B ionic Ca. to raise it to 400. My Total alk is at 5, can't get a reading for Borate Ca. and I don't know why. It has run without the reactor about 1.5....so I'm thinking maybe it's all Carbonate? I left the PH controller settings where they were, High at 6.60, Low at 6.20 and the effluent still at 30ml/min. Am I ok?

[Weatherman]

Let’s see…

To start out, maybe a few definitions are in order. Total alkalinity in seawater looks like this:

TA = [HCO3-] + 2[CO3--] + [B(OH)4-] + [OH-] + [Si(OH)3O-] + [MgOH+] + [HPO4--] + 2[PO4---] - [H+]

The first four terms on the right side of the equation are bicarbonate, carbonate, borate and hydroxide.

With our test kits, we really don’t have a way to distinguish between the various species (as chemists like to call them). Test kits, like Salifert, pretty much involve the addition of an acid into a seawater sample and measure how much of the acid is required to drop the pH of the sample down to some level where the dye color changes from blue to red. We then get a “total alkalinity” reading in dKH units or meq/liter units. Since carbonate and bicarbonate are such large contributors to the total alkalinity, an assumption is made that the alkalinity the test kit is measuring is mostly from carbonate and bicarbonate.

If I were you, I really wouldn’t be concerned about trying to measure borate, since it only, normally, represents about 3% of your total alk.

For natural seawater, the alkalinity is somewhere around 7 dKH or 2.5 meq/liter. Anything in the range of 7 to 11 dKH for our reef tanks is fine (2.5 to 4 meq/liter). If your total alk is 5 dKH, it’s too low. If it’s 5 meq/liter, it’s too high.

For natural seawater, calcium is around 380 pm. Anything in the range of 350-450 ppm is ok.


So, the first question I have is:

What test kit are you using to measure alkalinity, and what are the units (dKH or meq/l)?

[Viv]

gees, I'm at work...as soon as I get home I'll take a look...don't recall the manufacture off the top of my head. The test kit does Total alk, borate alk, you subtract the borate alk from total alk to get the carbonate alk....that's what I did....I always got 5meg/liter Total alk, about 1.5 Borate alk, leaving 3.5 as the Carbonate alk. The "tips" section states that the Borate should be 1.5-2.0, but not at the expense of Carbonate.
My question resulted because this time when I tested I got a Total alk of 5, but could not perform the Borate part 'cause there was never a color change. I know it wasn't the chemicals because I use the same chemicals to get the Total alk....that's why I figured maybe its all Carbonate....Will let you know the manufacturer when I get home , just blank at the moment for the name (as soon as I sign off, I'll remember!!) I have a feeling I'm gonna get told to go get Salifert, and yes I should by now know better....

[Viv]

It's called Seachem Reef Status, if that helps....Salifert, huh? I thought this was a pretty good chemistry test kit. It also measures Mag.

[Weatherman]

Originally Posted by Viv

It's called Seachem Reef Status, if that helps....Salifert, huh? I thought this was a pretty good chemistry test kit. It also measures Mag.

Here's a not-very-positive review of that particular test kit:

http://www.advancedaquarist.com/issu...e2003/chem.htm


Borate alk should be something more like 0.15 meq/l. If the "tips" section of your test kit says it should be ten times that amount, it's wrong.

[Viv]

Oh, Kaka! I'm on my way to a store! According to that, I don't have a clue as to where I'm at with my tank...I'll be back after I find another test kit...hope somebody carries the Salifert around here-never see any...I'll post later when I get the new kits and results....

[Weatherman]

What kind of salt mix are you using?

Seachem salt mix has a reputation for having ridiculously high borate levels (which may explain why the "tips" section of the Seachem test kit suggests such high borate alk is ok).

[Viv]

What a mess I've got. Went to the store, only have petgoods and petco locally and nobody has Salifert. Tomarrow to the LFS, for sure and I'll get all new and throw out the crud...Did a 150 gal water change...lead to PH, 8.2, Calcium 460, the reading on the controller is 6.74....my thought is that the Calcium is too high and I should adjust the High of the Controller. It is set for 6.60, or maybe slow the effluent? I'm totally lost and confused....the fish and corals are looking fine, just have no idea where I'm at....

[Viv]

Oh sorry forgot to post salt. I'm using Instant Ocean. The test kit for Ph and Calcium from Aquarium Pharmaceuticals.

[Weatherman]

Originally Posted by Viv

What a mess I've got.

It's really not all that bad. Just a little confusion, courtesy of our friends at Seachem.

I would suggest turning off the CO2 to the reactor (keep the circulation pump and effluent drip going), and stepping back for a bit. With a calcium level of 460 ppm and a, probable, carbonate alk of close to 5 meq/l, you are fine running without the reactor for a while. The other advantage of turning things off (and not dosing anything) is that you’ll get a good idea of your tank’s alkalinity consumption rate – a valuable piece of information for later when you start tuning the reactor.

The Seachem test really isn’t that bad if you use it for measuring total alk. That’s why I think your carbonate alk is somewhere close to 5 meq/l, since IO doesn’t have elevated levels of borate. LaMotte Test kits are, also, an excellent choice if you can’t find Salifert test kits. I actually prefer the LaMotte nitrate test kit over the Salifert nitrate test kit.

[Viv]

Will do! Thank you, will follow up tomarrow when I get new test kits and have true numbers! Again, Thank you!!!

[Viv]

ok, got the Salifert Ca. and PH. Alk will not be to the LFS until tomarrow evening...This morning results using both the Aquarium Pharmaceuticals and the Salifert were the same. Ca. at 400, PH 8.2 , Don't have the Alk test kit so can't tell unless do so with the Reef Status kit...so I didn't. The PH probe in the Ca. Reactor has gone up to 7.80.
I believe my setting for the Controller all have to be changed, and this is why...if the probe in the reactor is at 7.80, and I'm at 400 Ca. I would think this has to be my center number where the CO2 will shut off. So I should raise the High to 8.20...
I know this would appear as a high setting, but it kinda makes sense because there is very little stocking in the tank presently...I wanted to get all this straightened out before attempting to stock, so as not to put everything through a stress phase. But does this sound correct? I haven't touched the effluent flow, its holding at 30ml/min.

[Weatherman]

I've never used a pH controller, but I think they are, basically, a safety valve; they turn off the CO2 if the pH falls below a certain value, but don't do much else.

In other words, if the controller is set to turn off the CO2 at 6.5 and back on at 6.7, it doesn't really care if the pH is 12.8.