How to raise co2 levels?

[samh]

Hey guys,

I'm trying to increase my co2 level, the problem is though that my fish are already at the surface as it is. How can i increase my ppm without increasing death ?

My drop checkers are always yellow?

I'm running 3 reactors, one diy reactor with 20mm - 3/4 intlet outlet and clear 50mm (2") plastic pipe approx 30cm(1') long. The other is a sera 1000 reactor with 16/22 outlet/inlet and an ista brand reactor with 12/16mm hosing. Diy reactor is being pumped by a rio 1100 pump, the sera reactor has 1500l/hr and the other is running on an eheim 2217.

I also have 1x 3000l/h wavemaker and 2 x 2000l/hr nano wavemakers for added flow, which brings the tank around 8-10x volume
Also the tank has light surface rippling over the entire surface without breaking it.
Tank is 500L , 130g is 28" deep, 24"wide and 48" long

I've now reduced my lighting to 2 54w globes to see if that helps, I've recently recieved some ludwigia brevipes which have shown some drooping crowns. However growth is rather fast still. My ludwigia cuba hasn't started growing like it was before i had deficiency. I'm wondering if these plants are slow to recover from deficiency?

Main Question
Is how i push higher levels?
Could too much fish cause the fish to go to the surface prematurely?
Could tank depth vs surface area have any impact?
Can i increase my reactor diameter and length and install a higher flow pump to churn up co2 greater and faster?

Thanks
Sam

 

[samh]

Also forgot to add, I am using a ph controller but only as a safety precaution. I have the bubble rates high before lights on so the controller ticks off before the lights turn on. However before the lights turn on i then adjust the bubble rate so it's on all day at the level the controller is set at(which is fish gasping point atm). It will only click off if it goes to high maybe only once during the photoperiod.

Water parameters are,

kh 4 using 4 tsp khco3 after water change
gh 5 using caso4, mgso4 during week * see below
ph (during photoperiod) 5.85
ph at night 7.2

dosing EI
3x 1.5tsp kno3 a week
3x .5 tsp plantex csm+b a week
3x .25 tsp kh2po4 a week
3x 3 tsp caso4 a week
3x 1 tsp mgso4 a week
3x .5 tsp chelated iron a week

 

[dutchy]

I've now reduced my lighting to 2 54w globes to see if that helps, I've recently recieved some ludwigia brevipes which have shown some drooping crowns. However growth is rather fast still. My ludwigia cuba hasn't started growing like it was before i had deficiency. I'm wondering if these plants are slow to recover from deficiency?

Could be, plants take around one to two weeks to adapt to changes in their environment.

Main Question
Is how i push higher levels?

If I read back it seems like you already hit the maximum. High O2 helps.

Could too much fish cause the fish to go to the surface prematurely?

I don't think this matters.

Could tank depth vs surface area have any impact?

Surface area has an impact on gas exchange. Less surface area means less outgassing of CO2 but also less uptake of O2.

Can I increase my reactor diameter and length and install a higher flow pump to churn up co2 greater and faster?

The bigger the reactor and the higher the flow, the more CO2 you can dissolve.

Anyway if you reach the fish limit, you're at the end of the usable range. The only way you could go is to reduce CO2 demand by using less light, which you already did. Maybe it's just a matter of time.....

 

[samh]

Thanks for that dutchy,

there have been times when everything has worked with more lighting but i don't know what i did to make it good. I'm hoping 108w of hot5 with reflectors @ 70cm (28") will be high enough for most plants like ludwigia cuba-glandulosa-brevipes-palustris-arcuata, nesaea triflora-pedicellata, ammania gracillis and limnophila aromatica.

I'm going to use a 90mm diameter reactor as thats the most accessible clear pipe size available to me and i have a spare rio 12HF which i might use to run and i'll hopefully see an improvement in that.

I was thinking that 500l in volume with 120 x 60cm =7200cm2 surface area might not be enough for o2 exchange via surface rippling but i have no knowledge or experience to support that maybe someone may be able to help.

 

[dutchy]

Keeping a spreadsheet with dates, measurements, changes and remarks (Wow! great plant growth) is very valuable.

I have to admit you're not using a lot of light now, 3 x 54 Watts should be fine. Anyway, try for a while with two bulbs and watch carefully what happens. Your plants will always tell you what they need.

I don't think you'll have a problem with gas exchange, this is more for narrow tanks with stagnant water.

 

[samh]

Thanks Dutchy,

I have trouble discerning between insufficient light and co2. The plants i was using as an indicator were alternanthera reinecki and limnophila aromatica. When aromatica's lower leaves melt but the stem stays healthy, and the crown has nice tight leaf whorls, is this light or co2?

 

[dutchy]

with Aromaticas it can be both. Bad CO2 will make it worse, but also light is an important factor. That doesn't always mean you should increase light. Shading or crowding plays a big role in these plant groups. Best is to plant them so leaves from individual plants don't or only just touch. Don't put them to close against the back of the tank, leave an inch of space.
More light helps, but too much light wil give you algae. With aromaticas is easy to see if you give them enough CO2. When the leaf size increases, they are happy. If you can grow them up to 5 inch in diameter, you give them enough CO2.

I got a lot of improvent with these plants doubling the PAR from 40 to 80 (not Watts!!!!) Of course I'm not advizing to just use more light. You should use the lowest possible light at which your plants still look good and healthy. That's different for every tank, which depends on layout, plants you use and light setup.

 

[samh]

That might be my problem with L. Aromatica, i've been planting the stems in groups of 2-3 stems. 5" that's an awesome effort, i think i've only ever got them to maybe 2.5-3" max at maybe 20cm high? I'll re-plant them further apart and go from there.

 

[Left C]

... Also the tank has light surface rippling over the entire surface without breaking it. ...

... my fish are already at the surface ...

... My drop checkers are always yellow ...

... High O2 helps. ...

... Surface area has an impact on gas exchange. Less surface area means less outgassing of CO2 but also less uptake of O2. ...

I would increase the surface rippling and/or run an aerator/airstone at night.

This will allow more O[SUB]2[/SUB] for the fishes. If the drop checker turns to a more greenish color after doing this, you can crank up a bit more CO2 to get up to your drop checkers back up to their yellowish color.

Since water can be 100% saturated with both CO[SUB]2[/SUB] and O[SUB]2[/SUB] separately and independently of each other. And, water can hold much more CO[SUB]2[/SUB] than O[SUB]2[/SUB]. This is why I'm suggesting adding more O[SUB]2[/SUB] with a corresponding increase in CO[SUB]2[/SUB].

 

[samh]

So if i increase o2 at night via an airstone this will increase the o2 saturation during the day as well?

 

[dutchy]

Not necessarily, but it will give you a head start if O2 is low now. The rest depends on how much gas exchange can take place during the photoperiod.

 

[Left C]

If you increase the surface rippling 24/7 by a little bit and run an airstone at night, you might have more available O[SUB]2[/SUB]. I say might because it depends on how much pearling that you have and when I occurs during the lighting cycle.

If your tank is pearling like crazy shortly after the lights come on, the drop checker is yellow and the fish are at the surface sucking air; you certainly can't bump up the CO[SUB]2[/SUB] any more. You tank is at or very near the 100% saturation level for O[SUB]2[/SUB] and your CO[SUB]2[/SUB] saturation is high.

But, if you have less pearling than this, you have room to tweak it.

 

[samh]

The earliest pearling comes on about 2-4 hours into photoperiod i'm only running 108w of t5 so there's not heaps of light. The drop checker has lag so the ph controller is set at the level the fish gasp and drop checker is yellow. Once i wake up i then turn the bps down so the co2 stay at a constant level all day not cutting on and off. This seems to produce more pearling than letting the ph controller turn it on and off.

So at the moment. lights on - fish at the top, drop checker yellow and no pearling. approx 2 - 3 hours in, fish go down plants start to slowly pearl. Plant growth has improved in ludwigia brevipes, L. glandulosa and rotala vietnam and wallichi. Ludwigia sp cuba hasn't shown much improvement at all. Ammania gracilis is growing a lot better now as with the nesaea pedicellata. Its the cuba which is making me think theres still something missing. Last time it stunted and died back once i fixed co2 it was the first to grow back.

 

[Left C]

... The drop checker has lag so the ph controller is set at the level the fish gasp and drop checker is yellow. ...

Are the fish gasping all night?

... Once i wake up i then turn the bps down so the co2 stay at a constant level all day not cutting on and off. This seems to produce more pearling than letting the ph controller turn it on and off. ...

How do you know how much to cut it down? This step and the above scenerio just doesn't sound right.

... So at the moment. lights on - fish at the top, drop checker yellow and no pearling. approx 2 - 3 hours in, fish go down plants start to slowly pearl. ...

It sounds like your O[SUB]2[/SUB] level is low.

... Ludwigia sp cuba hasn't shown much improvement at all. ... Its the cuba which is making me think theres still something missing. Last time it stunted and died back once i fixed co2 it was the first to grow back.

Not sure what's wrong. Plants need O[SUB]2[/SUB] 24/7 too.

 

[samh]

No fish are only gasping for the first 1-2 hours max of the photoperiod only. They're fine for the rest of the day and night.

Just pointing out i have the solenoid connected to a ph controller which is set on a timer. I use the level of the controller as another reference guide along with a drop checker and the fish gasping point. The ph on the controller is set in accordance with the fish and drop checker

Co2 is coming in via 3 reactors so i can't give a bps. I have the bubble rate set high to start off with so it only takes 1 hour to reach the desired level which is fish gasping point and a yellow drop checker. Then once that's reached i then re-set it so the bubble rate keeps this level for the rest of the day. I judge this by the ph level on the ph controller.

This means the co2 isn't being switched on and off all day by the controller and a constant set rate keeps co2 steady, like how a normal timer set-up would work without a controller. I hope i made it sound clearer

So
6.00 am aerator off
7.00 am co2 on, ph 7.2
8.00 am @ lights on ph 6.05 drop checker yellow and fish gasping
9.00-10.00 am fish stop gasping and plants start pearling ph stays at set level 6.05
4.30 pm co2 off
5.00 pm lights off
5.30 pm aerator on

The fish don't gasp without the aerator i just have it as a preventitive. They can get enough o2 at night by the surface rippling.

Sam

 

[Left C]

You explained yourself very well both times. I just wondered if the fish were stressed for more than just a hour or two. Did you recently add the aerator? You can adjust the timer on the aerator if you need to. I was thinking that the oxygen level was low. Maybe it isn't. ??

 

[samh]

Oh cool, Its hard for me trying to get my head around it. I'm just going to drop the level by .05 every week regardless of the fish and see if that improves. I think the rainbows might be being whimpy and being over sensitive than they need to be as they go down from the top as soon as they see me so they can't be that stressed... i did drop it like .07 and i got crazy pearling maybe 20mins into the photoperiod, if i can keep this up hopefully the plants will improve without too much death.

Sam

 

[dutchy]

Fish gasping point should never be the "desired level". You can use it as a test to determine where the maximum is, but I would never submit my fish to something like that every day.

It is possible to have perfect plant growth without overdoing the CO2. Just use less light which will reduce CO2 demand. Since you did that just recently, did you give the plants enough time to adapt? It looks to me that's just only a week ago....

 

[Tom Barr]

My fish are fine and I do not need to gas them at all, their behavior changes if I get too high before they start to gasp also.

 

[hbosman]

I watch the gills on my Cardinal Tetras. When it appears that they are breathing heavy while stationary, I tweak the bubble rate lower. My Hengel's Rasbora's seem to tolerate higher levels than the Cards so, It appears that some species are more sensitive than others.