Dkh Help!

[jonifive]

Hi all,

Doing my fortnightly test regime I found the dKH of my tank to be 6, it's usually 11 dKH!!!!

I buffer my RO top up, but other than that I do nothing else. I was wondering what in your opinions was the best way to address this?

Also is this why my pulsing xenia has shrunk and stopped pulsing over the past few days?

"Help me Ultimate Reef Jedis, you are my only hope!"

:bow: :thumbsup: J

[jonifive]

C'mon guys any ideas????

:lol: J

[hairyduck]

test for calcium and magnesium, if your magnesium is low (less than 1250 ppm) you dkh won't be stable, same for calcium

[~Tony~]

What are your Mg and Ca readings?
And what are the Alk, Mg, Ca reading of your fresh salt water mix?

As hairyduck says, you need your Mg above 1250 first.
Also Ca & Alk interact. If your Calcium is high it will tend to push the Alk down.

If your Nitrates are rising this will also depress Alkalinity. Alkalinity is consumed in the first stage of the Nitrogen cycle, though returned in the final anoxic stage. If you export Nitrates (eg water changes) then that Alkalinity is not returned.

The simplest way to raise dKH is with Bicarb of Soda, available from the supermarket. (Make sure there is no raising agent in it - aka Baking powder)

I seem to remember reading in Calfo that Xenia are particularly sensitive to low dKH.

hth
Tony

[jonifive]

Thanks again Tony and Hairyduck

My Calcium was 420 last night. I havent tested the magnesium, so I will get a testkit this weekend.

My nitrates were the same as always 0ppm, but I don't know how acurate the test kit is, it's not a salifert. I woulds assume there would be some trace of nitrate.

So, do I add bicarb to my top up water or drip it into the tank? And does anyone have an idea of how much bicarb per litre to mix, sorry to sould like a newbie, but this is the first time this has happened to me, thanks guys....

:thumbsup: J

[~Tony~]

Calcium is good :thumbsup:

Best to mix the bicarb with RO water and drip it in slowly. You could just add it to the topup water container, but I find a good way is to use a 2lt pop bottle of RO+bicarb as the topup water source for a day. That way you are monitoring the dose.

1 level teaspoon (5g) of bicarb will raise your Alk by 0.75 dKH in your 300 lt (?) tank, dripped for a day.

hth
Tony

[GaryM]

Best to mix the bicarb with RO water and drip it in slowly. You could just add it to the topup water container, but I find a good way is to use a 2lt pop bottle of RO+bicarb as the topup water source for a day. That way you are monitoring the dose.

I fill my 2 litre jug with tank water then mix in bicarb and back in slowly so as not to drop the ph quickly. Is there any difference between mixing bicarb with r/o or tank water to drip into system ?

[jonifive]

Thanks again Tony mate

Ive got a perc 120, 104 gallons i think. Ive already sent the wife out for bicarb!!!

What test kit do you use for magnesium? my LFS doesn't stock Mg test kits (says-whats the point!) great help that is.

I'll have to order one off the net.

Hopefully in a couple of weeks my xenia will start pulsing again!!

Thanks again

:thumbsup: J

[~Tony~]

That will be 104 US gals = 394 lt.
Take off the thickness of the glass, internal partitions, pumps, skimmer etc.
Then the live rock and sand etc
You are probably left with 300-330 lt of water.

I'd use 1 tsp a day, and check your Alk daily until it is raised ok. 8 dKH would be good.

I use Salifert Magnesium test kit.

Again, check the contents. It should be Bicarbonate of Soda only. (If she gets Baking Powder send her back to the shop :P )

Tony

[~Tony~]

Originally posted by GaryM@Oct 28 2005, 16:47
I fill my 2 litre jug with tank water then mix in bicarb and back in slowly so as not to drop the ph quickly. Is there any difference between mixing bicarb with r/o or tank water to drip into system ?
No, only that you can add the RO+bicarb as top-up water and hence slowly.
If you have the patience to take it slow then the jug method is fine.

[kim]

I'm not sure about adding the bicarbonate to a jug of tankwater. :unsure:

If you add about 1 teaspoon to 2l of water to raise alkalinity in your 300l tank by 0.75 dKH, then (as you can guess) the dKH of the water in the jug will be immense. Eg if it's RO, it will be 0.75 x 300/2 = 112.5 dKH (40 meq/l). :o

If you start with tankwater, you have about 10 meq/l Calcium and 50 meq/l Magnesium (plus a bit more carbonate) - and once the precipitation starts, that's more than enough to take out out all of the bicarbonate you are hoping to add.

You might try it for fun. Don't drink it, it just looks like milk ! :lol:

kim

[excentric13]

sorry if im hijacking but im having the same prob with balancing everything is looking great in tank so not realy worried ok my stats are.
salt 24
ph 8.4
amo 0
nitri 0
nitrate 15
cal 392
mag 980
kh 7
phos 1.0

which is best to ajust first any help is apprisiated (cant spell) thanks Val

[jonifive]

Many thanks again guys, i'll post the results as they come in :thumbsup:

Val, you really have opened a chemical can of worms this time :lol: Good question tho, any info on this sort of chemistry is brilliant.

Got to build a simple drip system today, and get a magnesium test kit!!!!

:thanx: :bow: :thanx:

[jonifive]

Tony & Kim....are you mad scientists?
:P

J :thumbsup:

[jacksok]

Originally posted by jonifive@Oct 29 2005, 10:38
Tony & Kim....are you mad scientists?
I think you are half right :whistling: :D

[jonifive]

Hello, just to update the dKH situation,

I have made a DIY dripper to add my 2ltrs RO + 1 table spoon of Bicarb to the tank. This has replaced about half the top up needed per day in the tank, got the idea here....

http://www.reefwebsites.com/agu/kalkdrip/

Works really well. So far I have added three days worth (six litres ish) to the tank at one drip per second. My test today showed an increase from 6dKH to 7dKH, so it is slowly working.

I'm still waiting for my Mg test kit just to see the state of play. I'll let you know as we progress.

Cheers J :thumbsup:

[peterp]

J.

We too have had problems with fluctuating DKh & Ca, we were forever adding supplements but not being able to stabilise readings.

In the end splashed out on a Ca reactor. The one we went for was the AQ 1000 pressurised reactor. With a lot of initial advise on the set up from Andy Caine

It has been working for 1 month now and after a lot playing about and fine tuning we now seem getting stable results.

For the last week or so the tank readings have been stable at,
DKh 9.6 to 9.9
Ca 420 to 430
Mg 1320
We always test at approx. the same time of the day to get a truer average reading.

After a lot of fiddling about we have the reactor set at the following;
CO2 into the reactor about 120 bubbles per min (hard to count accurately)
CO2 into the reactor for 3½ hours per day mid photo period (Min pH of the reactor is 6.35 with the CO2 on)
Reactor flow into tank approx 1.5 litres/per hour.
Reactor flow into the tank is left on 24/7.

With this the max readings of the effluent from the reactor during the dosing period are;
DKh 35
Ca 580
Min / Max pH of the tank fluctuate between 8.15 with the lights on and 7.75 with the lights off.

This seems to be working for us at the moment, hope it is of some help to you.

Pete

[jonifive]

Thanks Peter,

I'm seriously thinking of going this way as well. But finances wont allow at the mo, (or is that 'er indoors!!)

Any chance of a photo of your calcium setup?

Thanks for the info.

J :thumbsup: