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Do water changes cause co2 fluctuation?

Niall

Member
Joined
1 Jun 2019
Messages
117
Location
Dublin, Ireland
I do a 50% water change every Sunday evening during the co2 and lighting period. Is this bad practice? I have some different algae issues that I am trying to get to the root cause of. Some point in the direction of co2 fluctuation, could this water change be counted as a fluctuation? Should I not inject co2 on water change day?
 
Good question. I do water changes during the lighting period too and wondered how about the CO2 swing and potential ph swing would affect the tank and livestock. Fortunately I've not experienced any algae issues that I think may be linked though

Be interested to hear what other peoples thoughts are
 
I do a 50% water change every Sunday evening during the co2 and lighting period. Is this bad practice? I have some different algae issues that I am trying to get to the root cause of. Some point in the direction of co2 fluctuation, could this water change be counted as a fluctuation? Should I not inject co2 on water change day?
What algae do u have?Got a picture of yr tank?As well as any params that u have.Changing water will reduce co2 temporarily.
 
Doing a WC during the CO2 period will cause a fluctuation in CO2 on that day which may help to the precipitation of algae issues. Not having the CO2 on on WC day would only make the fluctuation worse.

I always do my WC before CO2 on to avoid these fluctuations and will even delay the start of CO2 on and lighting etc if I need more time ( Delaying CO2 on and lightning is a PITA for most folk but with My PLC and @ian_m tankymytank software makes it very easy to do so I do use it from time to time)

Is it causing the algae issues is a tricky one to confirm and a lot will depend on lots of other things eg like the amount of DOC in your tank also. Also places like Aquarium Garden and Green Aqua also do there WC during the photo/CO2 period as they do it when they are open OFC. So the potential of issues is obviously tank dependant.

I would try to avoid WC during CO2 period if you can but if you cant do it late in the Photo period.

Couple of useful Quotes of Clives

we know that when the plant senses that high concentrations of CO2 is available, it responds by reducing the production of expensive Rubisco. When it senses a lower CO2 concentration it must increase Rubisco production, however because this protein is so complicated and heavy, the increased production requires 2-3 weeks in order to change the density in the leaf to match the new gas concentration level. So it is much easier to reduce production than it is to increase production. When increasing gas injection therefore, it hardly takes any time to see an improvement in health. When lowering the concentration, the plant will suffer because it must now ramp up Rubisco production to account for the loss of CO2 availability.

When increasing the light, the plant must reallocate resources from Rubisco production/maintenance in order to deal with the increased radiation. This may entail new pigment production for protection. When the light is reduced, the plant then reallocates the light gathering proteins and can devote them to Rubisco production/maintenance.

So when we mess around with light and gas, we have some degree of predictability.
What I mean is that if you are struggling with CO2 stability, or are having difficulty keeping high concentrations, then it's best to focus efforts on the first half of the photoperiod and not worry so much about the second half. If you are running very strong lighting then you are really pushing the plants and it's necessary to have the CO2 going. After 4 hours, if you turn the gas off, the water stays saturated for a couple of hours after the valve closes and the concentration trails off. So if you have an 8 hour photoperiod and you turn the gas on 2 hours before lights on, you can turn the gas off after 6 hours. So the gas is still running for 8 hours but it's on-off cycle is offset by the amount of time you turn it on prior to lights on.

There is no need to run the gas for 10 hours therefore.

Plants don't really run their photosynthetic machinery for the full day anyway. Under normal conditions, after 4 hours or so they start to shut down, so that's why CO2 isn't really needed for the full photoperiod.

Long photoperiods benefit algae more than they do plants, especially if it is high intensity.
The long photoperiod is more or less for our enjoyment.

Clive isnt talking about WC but we can use the information and relate it to the WC also. The CO2 flucuation would be transient (assuming your CO2 is normally stable!) So avoiding the first 4-5 hours of photoperiod would be my recommendation as the plants would have had there fill of CO2 so less chance of causing issues
 
What algae do u have?Got a picture of yr tank?As well as any params that u have.Changing water will reduce co2 temporarily.

I have cladophora, green thread, green spot, bba and hair algae.
It's 50 litres
Twinstar 600S running 65% on 7 hrs plus 30 mins ramp up and down.
Filter is oase biomaster thermo 250 with Seachem media and puragen
Co2 is on 3hrs before light and off 1 hr before, getting 1ish ph drop
Using ei ferts as per instructions with water change on rest day
Kh is 6
Ppm is high due to ei ferts
0 ammonia
0 nitrite
Nitrates are about 10mg/l
 
I have cladophora, green thread, green spot, bba and hair algae.
It's 50 litres
Twinstar 600S running 65% on 7 hrs plus 30 mins ramp up and down.
Filter is oase biomaster thermo 250 with Seachem media and puragen
Co2 is on 3hrs before light and off 1 hr before, getting 1ish ph drop
Using ei ferts as per instructions with water change on rest day
Kh is 6
Ppm is high due to ei ferts
0 ammonia
0 nitrite
Nitrates are about 10mg/l
How planted is yr tank and how much co2 are u injecting?
 
20191106_202658.jpg
 
My drop checker is lime green with a ph drop of 1ish. I am going to do a ph profile today and post it up.
 
One thing that has just occurred to me. I replaced my co2 reg 1 week ago because my old one would never shut off completely. When it was off it would still let through 1 bubble every 7 or 8 seconds. Since my new one is installed my algae is much worse. I have read about having co2 on before daylight does anyone do this? My tank does get daylight but it is not beside a window.
 
Well it is normal to get the full pH drop before lights on OFC which normally takes 2-3 hrs, but natural daylight is tricky. I sheild my tank with hardboard on one and a cardboard cover on the other to the sides that get natural light
 
Well it is normal to get the full pH drop before lights on OFC which normally takes 2-3 hrs, but natural daylight is tricky. I sheild my tank with hardboard on one and a cardboard cover on the other to the sides that get natural light

My room isn't particularly bright and the tank is pushed into an alcove with 10cm gap around the tank so the 3 sides are quite shaded.
 
Just noticed your co2 bubbles are going straight up.

Think filter was off for Pic ;)

My room isn't particularly bright and the tank is pushed into an alcove with 10cm gap around the tank so the 3 sides are quite shaded.

any light level algae will use and thrive so no light is best option when when lights are off

upload_2019-12-1_12-44-46.png
 
This is my ph profile so far today and I don't think it looks too good. I'm not even getting a 1ph drop with co2 on 3 hrs before lights. Would an inline diffuser help with this or will that only help with distribution?

12pm 6.8
1pm 6.8 co2 on
2pm 6.5
3pm 6.3
3.30pm 6.2 light ramp on
4pm 6.1 light on full intensity 65%
5pm 6.1
6pm 6.0
7pm 6.0
8pm 6.0
9pm 6.0

Lights will be off at 11.30pm with ramp down starting at 11pm.
 
Hi all,
Do the plants really look that pale? If they do, it suggests you may have an iron (Fe) deficiency. Iron is difficult to <"keep in solution">.

You may have hard water in Dublin, if it comes from a limestone aquifer? or very soft water (if it comes from the Wicklow mountains). Iron deficiencies are much more likely in hard water.
Using ei ferts as per instructions with water change on rest day
Does that include <"magnesium">?

cheers Darrel
 
Hi all,Do the plants really look that pale? If they do, it suggests you may have an iron deficiency. You may have hard water in Dublin, if it comes from an aquifer? or very soft water if it comes from the Wicklow mountains. Iron deficiencies are more likely in hard water. Does that include magnesium?

cheers Darrel

Hi that plant is nesaea gold so that the leaf colour. Although if you look closely the new leafs are deformed, I'm not sure why.
My water is not too hard in my area.
Yes the ei ferts contains magnesium.
 
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