[Bent17]

Hi all. I have a 200L planted co2 injected tank and have been in this hobby for around 3 months now. I keep finding random fish dead early morning. Water parameters are all good and I even dose with ferts. Kh and gh are alos good. It seems to point to the PH swings in the tank which could be shocking them and dying thats why I find them dead in the morning.. PH with co2 on is 6.6 and with it off is 7.3.. what would you guys do to try regulate the ph? Would putting co2 on for 1hr and off for the other repetitively do the trick? Normal co2 runs for 7hrs sonlike this it would be on for around 4 hrs.. opinions and suggestions on this? Any one else has same issue like me?

 

[Plinkploop]

That small of a ph drop shouldn't be killing your fish. In the off case that they're not getting enough oxygen overnight (not enough available when plants aren't producing) have you tried an airstone just for overnight? It's a start. If it works and there aren't more deaths maybe it is a co2 issue. If deaths continue than it's probably something else.

 

[Bent17]

Instead of an air stone what about putting co2 on and off throughout the day and night? Or not recommend?

 

[Plinkploop]

It's not going to really do that much besides mess with your plants if it's not the case. The safest and easiest way to check your theory is honestly and airstone overnight, IMO.

 

[Bent17]

Ok will a round airstone do? Would you think there is something else apart from my theory why they are dying?

 

[Plinkploop]

Yes, a round airstone is fine. I, honestly, couldn't tell you based on what information is provided what could be the problem. I just know that if it is because of too much co2 overnights an airstone will overnight will fix the problem, if it's not than it won't. Good luck on trouble shooting!! I hope this is enough to fix it!!

 

[jake21]

It is unlikely the ph change because usually it is change in water chemistry that shocks the fish not ph change due to co2 addition. If it was additive co2 killing the fishes than others would have the same problem (i have a co2 injected tank and haven't had a death in 8 month - the last death i had was one of my kubotai jumped out). More details would be required to understand what is happening but at the end of the day i would look elsewhere than co2 issue. The only way co2 is likely to kill the fish is due to lack of oxygen (as others mentioned) but that depends on level of injection (you said it is .9 drop which is close to the max you want). Turning the co2 on/off during the day will cause a lot of alge and likely bba. I run my co2 from 1 hour before the lights come on until the lights go off. I do not have an airstone but i do have a sponge filter and decent surface current.
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You could try reducing the co2 slightly if the fishes are showing distress due to lack of oxygen.
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Btw if you are going to add an airstone i would kill two birds with one stone and add a small sponge filter instead.

 

[Bent17]

If its not linked to ph drop then im really lost.. could it be linked to dosing excel also with co2?

 

[pauld738]

Definitely not pH. Lack of oxygen, quite possible. But don't rule out disease either.

Curious though, how are you testing pH?

Excel maybe? Definitely stop dosing right now until things settle down. And why are you dosing excel and co2? I understand if battling algae but long term there are other, more effective ways to combat algae.

Substrate? Dirted?

Ammonia in the morning? Ammonia is less toxic at 6.6ph than it is at 7.3ph. Just a thought.

Lastly, what are you using for water changes? Any water softener in the mix?




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[Bent17]

I am testing ph with the API master test kit. Taking reading every 2hrs to see no spikes are there..

Excel im using is against algae. I use excel, flurish, potassium, nitorgen and iron. I turned off the autodoser today and will start with Evolution Aqua to see if it makes a difference

I do 50L water change weekly and mineralize it.

 

[pauld738]

I do 50L water change weekly and mineralize it.

Yeah but what water? Remineralized to what with what?

It can be tough to diagnose stuff like this on a forum/online. So much info is left out. It's just the nature of the beast.

And at 50L on a 200L tank I'd say that is not enough. If you are dosing anywhere close to EI dosing minimum is 50%. But you haven't mentioned exact dosing so it is rather difficult to tell.

And I'd just say that liquid test kits leave out a lot of detail. Even at 2hr intervals, which is unrealistic long term. It becomes more important when you use co2. And have issues like this. If you can swing it, a ph monitor will provide much better insight into what is happening in the tank. Ph wise.



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[Bent17]

Yes I am waiting for my Ph pen to arrive but thats another week to go. My water is RO water with KH1 GH1 TDS 50 so i mineralize to KH 5 GH8.

Fert dosing:

Excel 5ml every other day
Flurish 2ml every 2day
Nitrogen 2ml very 2days
Potassium 1ml every 3 days

 

[Discusluv]

When was the last time you added fish or plants to tank?

Add an airstone- that's a simple fix.

 

[Bent17]

Last week. I had two rummy nose die 2 days after and I found an amano dead after 3 months in the tank

 

[Discusluv]

Last week. I had two rummy nose die 2 days after and I found an amano dead after 3 months in the tank

Disease or parasite ( Ich is the only one here that could kill that fast) would be very likely given you just added fish. But, because you are not seeing any symptoms on the fish it would be difficult to diagnose.
One of the most common is Ich-- look close at fish and make sure no parasites on fish.
The other is bacterial infection: Are the fish all eating? Any white or red areas on body, mouth, or fins? Any gasping for air or swollen gills?

 

[Bent17]

Photos of my dead fish.. i have like a growth on a fish but otherwisd perfectly normal..

Had a rummy nose with white lips so I got ot out..

 

[pauld738]

Yes I am waiting for my Ph pen to arrive but thats another week to go. My water is RO water with KH1 GH1 TDS 50 so i mineralize to KH 5 GH8.

Fert dosing:

Excel 5ml every other day
Flurish 2ml every 2day
Nitrogen 2ml very 2days
Potassium 1ml every 3 days

I agree it's more than likely a disease issue but just wanted to mention a few things that stood out to me.

Kh of 5 means you should have a starting degassed pH well above 7.3. just fyi. Probably more like 7.7-7.8ph.

If you are truly at 7.3 degassed tank water (note this can take upwards of 24-48hrs for water to properly degass, airstone speeds that up) , and Api test kits usually only go in 0.3 increments so that resolution makes it difficult, than you might have some excess nutrients in the tank complicating things?

Also, I noticed no Phosphates being dosed. Is that right? Depending on substrate used and plants in the tank that lack of phosphate could be helping to cause algae problems.

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[Bent17]

My substrate acts as a buffer.. i just stopped my seachem ferts and got my hands on the Evolution Aqua all in one fertilizer.. this included phosphorus

 

[Mark Fisher]

That small of a ph drop shouldn't be killing your fish. In the off case that they're not getting enough oxygen overnight (not enough available when plants aren't producing) have you tried an airstone just for overnight? It's a start. If it works and there aren't more deaths maybe it is a co2 issue. If deaths continue than it's probably something else.

Also, does your tank have a lid or is it uncovered? A tight-fitting lid can hinder O2 exchange.

 

[Bent17]

Yes its covered