Drop Checker with Inline Reactor

Sandgrownun

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Hi

I was previously running pressurised CO2 at 1 bps in a 240l through a bazooka style diffuser with a spray along the back of the tank for circulation and my drop checker was consistently a nice shade of green. I got fed up of the micro bubbles clouding the tank so decided to install an inline external reactor a few days ago. It is of the ceramic diffuser and turbo type to dissolve the CO2 into water on the way to the spray bar return. This has cleared the visual appearance of the water and there are no more micro bubbles however the drop checker changed to very dark green bordering on blue despite expecting better absorbtion/saturation of CO2 into the water with this method.

I have tested for leaks and cannot see any so I then doubled to 2 bps yet the drop checker still remains very dark green/blue. Is this normal and does the drop checker rely on larger bubbles breaking inside the bell to cause the reaction with the solution or is something else wrong as I am at a loss?
 
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Hi
The fine mist of bubbles could have been going into the drop checker affecting your reading making it look lower than it was.
Or the fine mist of bubbles could have been getting trapped on all the plant leave, staying under water for longer giving you better dissolved co2.
 

Sandgrownun

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Maybe. I am thinking that when there are micro bubbles in the water with effective water circulation many of these will make their way into the drop checker and effectively burst at the surface inside the bell and react with the liquid because there is effective gas exchange , however if the CO2 is completely dissolved in the water by a reactor and there is little to zero surface agitation inside the drop checker then there will be less gas exchange at the water surface inside the drop checker so the reading may show less CO2 even if there is more CO2 absorbed in the water than before. Hope that makes sense or am I talking rubbish:)
 

Zeus.

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Are you using a different diffuser ?
If so the working may/will be different and so will the size of the bubbles and the amount of CO2 injected will be different even if the injection rate hasn't changed.
If you change the CO2 diffuser for a different type you will need to change your injection rate to suit. So new pH profile.
 

Sandgrownun

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I suppose the specific question I am trying to answer is, is a drop checker an effective method for checking CO2 when the CO2 is completely dissolved in the water with a external inline reactor?

As I understand, the purpose of the inline reactor is twofold.
1. With traditional in-tank bubble diffusers the bubbles make their way to the water surface and burst into the air and are effectively wasted. The external reactor dissolves the CO2 bubbles into the water before the water enters the tank and therefore theoretically less CO2 is needed as there is less wastage.
2. Removes the appearance of cloudy water (at a distance) as there are no visible bubbles in the water

Prior to the reactor, at 1bps there was a healthy stream of bubbles from the bazooka diffuser located at the bottom back of the tank. These would float towards the surface but get hit with the water flow from the spray bar and get blown all around the tank however they would still get to the surface and burst into the air. I appreciate the some CO2 would dissolve into the water but it visually appears the majority is wasted. On the other hand, an inline reactor connects to the return pipe from the external filter and the CO2 is first passed into the chamber and is diffused through a traditional ceramic diffuser, the water is then agitated mechanically either with a turbo or media such as bio balls to dissolve it into the water. The water then of course returns to the tank.

So I can probably get a nice colour on the drop checker by increasing the rate of CO2 but this strikes me as counter-productive and defeats the purpose of the reactor. I suppose the only real test it to measure the relationship between KH and PH with and without the reactor running. I can see a 0.1 drop in PH but is this an accurate test without also measuring KH?

Pic attached of the reactor I am using. For some reason they are not readily available in UK unlike inline diffusers.
 

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foxfish

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There are many types of reactor, to achieve a bubble free tank would more likely require quite a large reactor.
Unfortunately large reactors are very thin on the ground and most folks have had to adapt vessels or build their own.
There are in line atomisers that distribute the micro bubbles via the return flow, and there are in line reactors that slow the flow down and allow the Co2 dissolve.
I have not seen the model you have but there are similar models that have been tried and tested on this forum... they are not a popular choice.
Testing the PH may not be that accurate in defining the actual CO2 content of the tank water but is a very useful way to see how your system is working and if the PH remains stable during the lights on period.
Never the less, obtaining a PH profile is the standard way to help set up your system .
Now we all know that individual sets ups differ from one to another however I think most tanks above 200 lt use a lot more than 1bps more like 6-10 would be average.
However if you are seeing strong plant growth and little algae then you are definitely on the right track.
 

Sandgrownun

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Thanks Foxfish.

Yes they are thin on the ground and I could only find two available in UK which dissolve the CO2 neither of which are branded and come from Asia. I have seen references to other brands in the forum, JBL etc but looks like these are discontinued probably because they are not popular as you say. Inline diffusers on the other hand are readily available but these don't solve the bubbles in the water issue do they? With the one I am using there is no bubbles in the water whatsoever however I need to determine it is doing the job and the CO2 is present in sufficient quantity.

I have no issue upping the bubble count to whatever is needed but I am wondering whether the drop checker is an effective way to measure when the CO2 is fully dissolved because of less gas exchange inside the drop checker . I am happy with the plant growth so far but the tank is only 3 weeks old and some stems are growing an inch overnight and look really healthy. Culture plants are also doing well but Crinum calamistratum and Rotala wallichii (culture) melted away in the first few days. I am just coming out of the other side of a brown algae bloom and no green algae yet fingers crossed and still early days to know if everything is ok. No liquid ferts yet and following the Tropica 90 day program.

I took my initial advice from the Dennerle guide at https://dennerle.com/en/guides/aquaristic/co2-fertilization/what-co2-concentration-correct

I am assuming I can get an accurate reading on CO2 by taking the carbonate hardness and PH directly from the water and comparing on the chart. Is this a more accurate method rather than relying on the drop checker?
 
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Yes the drop checker is effective enough at measuring co2 when the co2 is fully dissolved but not so effective when co2 mist enters the drop checker. So you are now probably getting a more accurate read than before with the co2 mist.
Less gas exchange just makes it take a little longer but you still get the same result. You could try the drop checker in a fast flow area of the tank.
You could test your reactor vs diffuser by measuring ph drop after running each one for say 2 hrs. Or just stick to the reactor with no visible bubbles.
 

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