23 replies to this topic

[kassysimon]

Hi guys.

Im using a co2 controller running from a PH probe. My KH is 11 and even with my PH controller set to 6.5 my CO2 drop checker remains a medium/dark green.

Previously my drop checker would be a light green with KH at 6-7 and PH at 6.6. Now my KH is up at 11 and all i have done is added more plants. I have not changed my regime at all and Im using the EI. but i have increased circulation with-in the tank.

I have also noticed that my plants no longer pearl as much as the used to.

With the KH and PH at these values i should be having a CO2 value of over 100ppm....

How can i lower KH and will this even help?

What is happening and what can i do?

Thanks.

[Anka]

Mate - I stongly recommend you pop into Aquotix and speak to Ollie in person. He will explain everything

(And while you're there you can buy some plants or fish )

[waruna]

Did you end up buying AquaSoil?

[kassysimon]

I placed the order and they didn't have it in stock so I waited and waited and they never got back to me so I'm just going to do DIY. Laterite and inert gravel.

[waruna]

Are you adding anything to alter the water chemistry?

[kassysimon]

Prime. According to the dose. 5mm per 200L.

Edited by kassysimon, 05 June 2012 - 09:27 PM.

[Rovik]

First of all, drop checkers IMO are inaccurate at times, however, not useless.

Something doesn't quite add up.
Either you messed up the KH test or your probe is not calibrated or something out of whack.

It happens all the time, our results are only as good as our calibration and equipment.
Remember that drop checkers DONT give measurements in PPM, they are just a GUIDE.

Unless you can get your hands on a proper CO2 titration test kit.

If what you say it correct: KH of 11" and pH controller set to 6.5...
Theoretically you would have around 106ppm of dissolved CO2.
Which would most likely kill all your fish.- That's over 3 times the normal dose for "high tech" tanks.
Given that this is under a standard environment and there are no other factors like other organic acids.

Please refer to the table below:



As I have said before:

A pH controller is a usefully tool, that will disperse the Maximum amount of CO2 to maintain A constant CO2 level...In other words "Set and forget".
And a pH controller will adjust to your plant load, add more plants and more CO2 will be dispersed, Sell the whole tank full of plants and hardly any will come out.
You also don't have to turn it off at night or worry about messing up the bubble count and killing your fish.
As long as you maintain the Correct KH and regularly Re-calibrate your probe its all to easy.

Ignore the drop checker, you have a pH probe .
Just cross check the pH it is reading with a normal pH test kit.



So my advice to you is:

Recheck your KH levels and calibrate your probe.
Also check the pH of the water with a good old fashioned test kit to see if it reads the same thing as the controller.
If your KH is correct at 11 degrees you have 2 options:

1. Dilute your KH by doing water changes with water that has a lower KH value. e.g. rainwater or RO water
If your target pH is 6.5 then you should have a KH of no more than 3-4 degrees. (refer to table)

2. Adjust your pH controller to a pH of around about 7.1-7.2 (Also refer to table) if you would like to keep your KH at 11"

Its all about finding your target ppm and pH given your water quality out of the tap.
If you get a KH of 11 Deg, the go with the flow, no point in wasting money on filtered RO.
The old saying: If live gives you lemons, make lemonade.


I understand that the table can be misleading because it doesn't in to account any other organic acids or bases.
Might be a good idea to test your BASE pH value...

The pH level of your tank water when it does not have CO2 injection.

To do this take a sample of your water out of the aquarium, let it sit for 24H in a cup and test...This will allow for the CO2 to be out-gassed.
If it sits higher than your target pH or the pH of your tank water your good.
However if it sits close or lower than your tank water, you may need to add a non KH base to neutralise the acid without increasing your KH.

If you need more info on this or elaboration, Pop into Aquotix.
I'm sure Ollie or the other staff have time for a quick chat.

Rovik.

[kassysimon]

As always Rovik... Your the man...but....
I've used a Sera test kit. 11 drops, 11 KH and my PH probe is spot on.

The reason I mentioned the drop checker is because the fish are all alive and well, not even the slightest sign of stress. So there is something strange in the neighbourhood.....

I will test the base PH and report back.

I will also work with my current KH and raise my PH point to 7.0 and monitor it for a few days.

By the way.....I have three drop checkers in the tank and they all show the same

I thought I had this sussed....

[Rovik]

Hmm strange:

Perhaps there is out gassing of the CO2.
Or its not staying in solution as it should.
The expert Chem Boffins can shed come light on this.

Might be worth talking to Ollie, Perhaps you can get your hands on a CO2 titration test kit.
There not cheap but they will give you a Exact PPM reading of CO2 to make sure everything is working as should.
Its obviously not where it should be because the fish are not gasping or dead, and the drop checkers and not the yellow.



Some thing like this: http://www.chemetric...ide (dissolved)

By the way, are you using tank water for your drop checkers ?

[kassysimon]

Perhaps there is out gassing of the CO2..........By the way, are you using tank water for your drop checkers ?

Hey mate.

Out gassing of the CO2? Out gassing from the tank......? There is only moderate surface agitation and no CO2 bubbles are exiting the spray bar which leads me to think that the CO2 is completely dissolved prior to entering the tank.

yes i am using tank water.

I will renew the fluid in the CO2 DC's tonight but I'm thinking they will show the same reading.

Thanks.

Edited by kassysimon, 06 June 2012 - 06:28 AM.

[waruna]

You need to use a 4 DkH solution to get an acurate reading.

Read this:
http://www.plantedta...4-solution.html

Regards.

[kassysimon]

You need to use a 4 DkH solution to get an acurate reading.

Read this:
http://www.plantedta...4-solution.html

Regards.

This is only really required when your using DC's as the sole unit of measure isnt it and since my KH isnt at 4 how does this help? Just to be used as a reference of 4KH V's PH?



I will make up a solution tonight and see how it reads.

Ill get back on here in about 2 hours to let the reading stabilise.

Edited by kassysimon, 06 June 2012 - 05:55 PM.

[Brett]

I would initially get your water tested by someone else (eg LFS) to check your test kits are accurate.
Then turn off your CO2 and repeat the test to get a new baseline.
Finally turn it back on again and see if the readings change.

Cheers
Brett
Look forward to hearing what the problem turns out to be

[kassysimon]

I have turned off my CO2 and tested the water.

KH is 11

Tapwater is KH8

Will hit up an LFS for a test tomorrow.

Here is a pic for you guys.
I will be moving in a few weeks so right now its just a grow out tank and not scaped.

Edited by kassysimon, 09 June 2012 - 12:44 PM.

[kassysimon]

and a before shot...

[Brett]

"I have turned off my CO2 and tested the water.

KH is 11"

I was more interested in the pH, it should rise when you turn off the CO2 and fall again when you turn it on.

Cheers
Brett

[kassysimon]

"I have turned off my CO2 and tested the water.

KH is 11"

I was more interested in the pH, it should rise when you turn off the CO2 and fall again when you turn it on.

Cheers
Brett

The PH has risen from 6.5 to 7.55 since the CO2 ran out on Thursday.

Edited by kassysimon, 10 June 2012 - 10:29 AM.

[Mr_docfish]

A bit of background (some already covered above)
In most aquariums without CO2 injection, you would expect to have about 3ppm of CO2 from decaying organics, bacteria and fish... so check the chart above (by Rovik) and you will see the base pH for a known KH with a CO2 level of about 3ppm (eg 5KH = 7.6pH)
This is the pH you would expect without CO2 injection, unless you have a high level of other acids, particularly from aquasoils, peat and almond leaves etc....
If the base pH without the CO2 injection is already low, you cannot expect to add CO2 to this without dropping the pH even further.
You either have to do water changes to dilute the acids, or add products like KOH (Potassium Hydroxide) which will directly neutralise the acids, allowing you to add CO2 without the pH dropping below preferred levels.
If you are using a pH controller, you have to consider base pH levels in order to be able to introduce enough CO2 to reach desired levels of 20-30ppm
If you are not using a controller and just counting bubbles, you will often find that the pH will either drop too low, or the CO2 will have very little effect, depending on the water quality at the time (I am currently experimenting on Dissolved Organic Carbons (DOC) and Volatile Organic Carbons (VOC) on the ability of CO2 to dissolve - I am showing that increased organics in the aquarium will prevent CO2 from dissolving properly)

CO2 has no permanent effect on KH - test kits may show a difference due to the nature of the kits though.... but this is an irrelevant issue - the problem is the KH is high, but the base pH is low.
Water changing with a source that is lower in KH is a good start to bring the KH below 6 for most plants.
If the base pH is still lower than you would expect, then add KOH to your planted tank to allow the pH to increase (this may increase the KH by a bit, but not as much as KH buffers would for the same pH increase)
If the plants are still not pearling, then check all other parameters - NO3, PO4, GH...{ and if you need to and have the kits - K, Ca (to compare with GH to work out Mg using a calculator) and if all else fails, there are CO2 kits - but that's for nutters like me.... }

If you are still struggling, then the best bet is to do regular water changes (weekly) and re-dose with the right amount of complete ferts, add NO3 if required and add nothing else... things will normally sort themselves out. Sometimes there is an overload of something in the tank from months of problems, and this takes time to flush out.... some things that happen in the tank, we cant test for.... hence the popularity of the EI method (flush and re-dose).

I hope you can pick something out of this to help you out - any particulars, feel free to PM me directly, sometimes I dont get to see every post on here...

Cheers
Oliver

[kassysimon]

Hi Ollie, and thanks for having a read.

In most aquariums without CO2 injection, you would expect to have about 3ppm of CO2 from decaying organics, bacteria and fish... so check the chart above (by Rovik) and you will see the base pH for a known KH with a CO2 level of about 3ppm (eg 5KH = 7.6pH)

I just want to confirm that the above is similar to what i have but i have a KH11 and PH7.6, i know this because i ran out of CO2 on Friday and as yet have not got my cylinder refilled.....maybe tomorrow.

the problem is the KH is high, but the base pH is low.

Just to make sure all is clear here....my KH is high and the PH is high too, not low as you mentioned above. Not sure if yours was a typo or if you misread the earlier posts. (there is lots to read) but just to confirm i have a base KH of 11 and a base PH of 7.6.

Injecting CO2 will lower my PH to 6.6 - 6.5 from PH7.6 (set with a controller) but the drop checkers are medium green, the plants dont pearl and the fish are fine. I should be over dosing the fish by that stage....

If the plants are still not pearling, then check all other parameters - NO3, PO4, GH

NO3 and P04 are good but GH is at 18. Could that be a factor?

If you are still struggling, then the best bet is to do regular water changes (weekly) and re-dose with the right amount of complete ferts, add NO3 if required and add nothing else

The above is what im doing, 50% water change per week, EI method dosing that includes KN03, MGS04, KH2P04, K2S04 and chelated iron. So are you saying to add nothing BUT KN03?


I have just remembered one thing of interest though.....!

I have used H202 weekly to combat BBA. i have used it for the last three weeks and come to think of it, this is when it all started. I have used the maximum dose stipulated but in the last two instances i havnt done a water change after wards. I actually dosed after my weekly water change so the H202 would have been in the tank for a week until my next 50% water change.

Just to be clear, I have done a water change since the last time i dosed H202.

Do you think H202 could be part of the cause?

Thanks again everyone.

Simon

Edited by kassysimon, 12 June 2012 - 07:06 PM.

[Mr_docfish]

Just to make sure all is clear here....my KH is high and the PH is high too, not low as you mentioned above. Not sure if yours was a typo or if you misread the earlier posts. (there is lots to read) but just to confirm i have a base KH of 11 and a base PH of 7.6.

At a Kh of 11, your base pH (at ~3ppm CO2) should be around 8.0... either way, the KH is considered too high.

Injecting CO2 will lower my PH to 6.6 - 6.5 from PH7.6 (set with a controller) but the drop checkers are medium green

This is not right - I would check the probe (soak in storage sol'n for 24hours then re-calibrate to 7.0 and then check it against 4.0 to see how accurate it is.

NO3 and P04 are good but GH is at 18. Could that be a factor?

GH of 18 is a bit high - but understandable if your KH is that high - it will come down if you can do water changes with water that has lower KH and GH - Keep the NO3 at around 5-10ppm and PO4 at 0.25ppm (depending on the species of plants you are keeping, can be a bit higher for some)

EI method dosing that includes KN03, MGS04, KH2P04, K2S04 and chelated iron. So are you saying to add nothing BUT KN03?

Are you adding trace? - try just a complete fert (go a commercial one so we can be sure there is nothing odd with any part of the EI - you can get back to that once things are back to normal, then you can troubleshoot once bit at a time) - and if the NO3 of the tank is less than 5ppm, then add KNO3. If you are feeding any fish in the tank, you would normally have enough PO4 available (PO4 is naturally in under supply int he wild, so plants will cope with low levels of PO4 for now) This will help narrow down the problem for now...

H2O2 itself breaks down into water and oxygen, so no by products... BUT.... it can stress plants out, particularly those that cant handle the high oxygen levels created (like algae cant handle it) and any organics that have come from the breakdown of algae and other muck in the tank may have an effect on the growth of the plants (Im getting back to my DOC/VOC issues - still early days atm, so I cant say exactly why these organics cause issues with some plants)
Either way, water changes can sort this out in the long run anyway....

See how things go once you get the water and the pH probe sorted.

Cheers
Oliver