pH drop

[DiscusEden]

Hi,



I've just set the new Sera computer controlled CO2 system up (8 days ago), and put fish in the tank 7 days ago (after a fishless cycle). The CO2 controller is set at a desired pH of 6.8. Water comes out of the tap at 7.6, ages after less than 12 hours to 7.2 with Seachem Prime. Before putting the fish in (from a 6.8 tank) , I added pH down, which dropped the water to 6.81 - 6.89 - the CO2 had dropped it to 7.0.

Since adding the fish, the pH has been steadily dropping, although it has generally held at around 6.60 - 6.68 for the last 3 days, including today. This is the first night I've looked after lights out on the tank, but it's now at 6.53. Do I panic? (Again). Discus are still swimming around.

What's causing the drop?

I did a 15 - 20% water change yesterday, which raised the pH to 6.7 temporarily. kH is 3.5, ammonia is 0. Lots of surface movement through spray bar & overhead filter outlet at other end.

Help please? Do I shut the CO2 off manually, or will this create a bigger swing up?

Sorry for the long post & thanks again guys!

[fishgeek]

if CO2 is computer controlled with solenoid and pH meter then your setting and an accurate probe solenoid system will then mean that CO2 is already off
well thats is what the system should be doing

the simple problem is increasing H+ ions , these will accumulate with denitrification or the normal maturation that occurs in a new tank with fish, ie the filter working to clear ammonia will liberate some H+ ions

low kH that you have means this process is more likely to alter your ph

what was the pH down you added?
i would be inclined to think that with a kH of 3-4 as you say you have adding some more would be useful
otherwise i wouldn't have a CO2 setup on at all

plants will utilise some of the Kh element in growth and sso lower this slowly aswell
when the lights are out plants respire jus like fish and us , this liberates more CO2 , hence the lower at night pH a sligt diurnal fluctuation is normal

in your instance i would be inclined to stop adding things ie C)2 off, and no more pH down
do small daily water changes to stabilise things

get back to us with your tap water Kh , if it is as low as you have stated then it needs raising if you wish to contiue with CO2

hth
andrew

[DiscusEden]

Thanks Andrew, much appreciated.

Will test kH tonight (have to go to work). Have switched CO2 off for now. pH currently at 6.48!

Haven't put any pH down in since 1 hour before the fish went in (none at the last water change, last dosing was 8 days ago). Used API brand. Only listed ingredient can find is "contains sulfuric acid". Used about 2 1/2 teaspoons for 520L.

Thanks again!

[Robdog]

I reckon your fish will be loving it. Provided they are all acidic water fish that is.
As long as they are gradual changes in the ph I don't think you have anything to worry about. If you start getting ph readings down around 5.0 or rapid swings in ph then alarm bells should start ringing.
Until then remember that in the wild, (and Brilliant's tank :wink: ) discus and cory species are found in water with ph readings of 4.? so you have a fair way to go before they start to get uncomfortable.http://www.masa.asn.au/phpBB2/images/smiles/rtaw_crossfingers.gif

[DiscusEden]

Thanks so much guys! Thankyou for the reassurance Robdog - very much appreciated!

You hit the nail on the head Andrew! I tested the water just now. 3.5 out of the tap, 3 (just) out of the water aging barrel, and 1 is lime green, 2 is yellow (so I'm guessing that's 1.5 to 2) out of the tank.

It's down to 6.47 tonight with the lights on and CO2 off. even knowing it can go lower before causing major issues, I think I still need to address it, 'cos it's showing no signs of settling yet.

I've got some Sera KH/pH-plus. It says 5ml raises 30L by 1 degree KH. The tank is 540L before adding substrate, log, etc. What is the kH I sould be aiming for in a discus tank, and how much should I be adding over how many days to get there?

Sorry for all the questions, but what sould I be adding to a 100L water aging barrell before changing the water when I get this sorted? Or should I keep adjusting the tank directly instead?

Oh, and at what point can I turn the CO2 on again?

Thanks again for your help - haven't tried this part of the game before!

You guys are unbelievably kind and helpful - thankyou!

[scott bowler]

DE the fish will tolerate the ph so dont panic about them and just work out what it is that is making the ph drop good luck with it DE scotty

[DiscusEden]

Thanks Scotty,
I think Andrew had it right & it's the kH being too low.

Sorry for the long post before, just trying to cram all the questions into one, rather than continually coming back with more.

Not panicking now, just trying to figure it out before it does become a problem (if it keeps going at the current rate - and it might not - I'm expecting to have another 2 days before it gets below 4.0).

Problem is, as the KH drops, the pH might swing quickly if my understanding's right, which could be a major problem. So I want to get onto it before this happens, but want to check how.

Getting longwinded again - sorry & thanks!

[Merrilyn]

DE your water has very little buffering capacity, and that's why your pH keeps dropping.

You can easily rectify the situation by adding more calcium to your water, in the form of crushed coral sand, or coral scraps or even shell grit (yes the stuff they use for cage birds). All of those will slowly dissolve and add calcium to your water, which will in turn buffer the pH and prevent a pH crash.

Start by tossing a handful in your ageing barrel, but you may need to add some to your tank as well.

You can put it in an old stocking, and simply hang it near a water flow.

[DiscusEden]

Thanks Merrilyn!

Will get some next chance.

Should I use the Sera stuff, or just rely on the shells?

[Merrilyn]

Just rely on the shells. The less chemicals you put in your water, the better.

[fishgeek]

DE where abouts do you get tap water with so little alkalinty, i think i shall move there when i return to australia
hope the beach is nice near you :D


if you intend to add C)2 fr plant growth i would be wanting the kH above 5 , the pants will utilise some of it in growth, you may also be adding fertiliser to get the best out of your plant growth

otherwise if it is the fish you are primarily concerned about, i am assuming discus , then low mineral water, as long as it is stable is ideal for most sth american fish

andrew

[DiscusEden]

Hi Andrew,

It's just Adelaide water. I'm in the hills, with the wildlife & the country, but 25 mins from the beach. Pleanty of places in Adelaide with the same water, next to the beach. And it's South Australia, so yes, the beaches are great. You'd be more than welcome! :D

I put a stocking toe in the tank filled with a generous handful of shells, hanging near a filter outlet, as suggested. Seems to be doing the trick. pH is back up to 6.51 - was at 6.59 until I started playing in the tank again tonight. Can't seem to keep my hands out, but now have plants! Lots of lovely plants!

Will turn the CO2 on tomorrow night if the pH is above 6.6. Unless you'd advise otherwise (still on controller set at 6.8.

Thanks again for all of your help and advice! Very much appreciated! I don't know what I or the fish would do without you all! :wink:

Oh, silly question maybe, but sould I attempt to regulate the hardness with the shells at all? (The amount of shells maybe?)

[Merrilyn]

Yes you can. Adding the shells will naturally increase the hardness of the water. Unfortunately I can't offer you a sure fire method. It's a bit of trial and error.

If the amount of shells you have in the tank now is holding your pH stable, then that's fine. That's all you need to do. If the pH keeps dropping, then add more shells.

Our Melbourne water is even softer than Adelaide. I regularly get a Kh reading of betweeen 1 and 3, which is perfect for breeding tanks with their daily water changes, but a real pain in grow out tanks and display tanks. I have shell grit in all my non breeding tanks.

[DiscusEden]

Hi again,

Sorry to keep on about this, but I'm still having trouble with this. I thought I had it sorted, but I was wrong! :?

I've got 3 bags of shells in there, each the size of a large fist. Spat it with the last one that I added a week ago & didn't wash it first - the water went cloudy at first, then came clear.

Did a w/c of 30% two days ago. The pH went up to 7.2, so I put the CO2 back on, with the controller set at 6.9. The pH has been around 6.7 since, which is great, but I can't put the CO2 back on & I'm getting brown algae which I'm told the CO2 should control. Oh, and I tested the kH today & it's blue at one & a strong yellow at 2. :?

Do I keep adding shells? Any other suggestions? Not to sound ungrateful, 'cos the principle you've given makes a lot of sense, but how much of the tank do I fill up with shells? How many do you have in there?

Thanks again for all of your help - I could really do with some more advice on this please, 'cos I don't seem to ba able to sort this one myself.

Thankyou!

[DiscusEden]

Please help?

[fish_r]

i dont know if this will help "hope it does" DE but this is a pretty interesting thread ?
http://www.plantgeek.net/forum/viewtopic.php?t=9138

[axl]

Hey,
i havent been on here for a while, now i have the same problem as you soft water out of the tap. My tap water is kh 3 so i add Bi carb soda slowly to the tank as i dont have a water aging barrel. i mix 1 teaspoon to 100 ltrs of water and that increases my kh to 6 where i want it. So if my ph is set at 6.8 on the controller which it is i have 33ppm of co2 in the tank perfect. So Bi carb soda is the the cheapest way to increase your hardness. The best advice i have been given is add the bi carb slowly to the tank so you dont get huge change. I mix 1 teaspoon in 500ml of water and add it to the tank slowly. I top it up when i take out 100ltr x 2 a week. Sorry for the long post any more questions im happy to help. cheers Axl ps also adding bi carb quickly makes the rise, so add 1 teaspoon daily so you dont get a big change.