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Discussion Starter · #1 ·
Hi all,

I am new to the forum and I would like to ask about the Carbo+ unit.
I know loads (if not all) of you guys hate this solution :D (I used the search function and went through the threads).

However, isn't it a good and easy alternative to reverse osmosis if one wants to lower the KH? (and also the GH, I noticed by comparing to the water from the tap that it's reduced)

I have a 180 Liters tank (that's about 47 Gallons), reasonably planted, and the water from the tap is around 8 or 9 KH.

I am only using the Carbo+ at 30% during daylight so the carbon plate should last fairly long.
I checked the KH in the tank and it was around 3 KH one week after a water change.
(I have the unit for a couple months now)
I changed the water again and it's 4 KH but I guess it will drop again.

So wouldn't it be a good solution to keep a low KH without all the hassle with reverse osmosis?
Specially if the fishes in the tank like softer water.
I only need to worry about the KH getting lower than 3, but then there are easy ways of increasing it to 4 or 5 : changing 15-25% of the water weekly or adding KH+ or KH/GH+ products.

And about the CO2 production, I have this CO2 long-term test Correct + pH thing from Dennerle. (being a new user, I can't post the link)
It shows 10gr/l on average, sometimes a bit less, not too bad for KH=3, and I could add a real CO2 injection system on top of that.

What do you guys think?
 

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You're looking at test strip readings and not what these systems actually do. If ALL you're worried about is the kH then you might be fine, but Co2 addition is acidic which is why pH drops when you add it to the water.

RO/DI water has been stripped of all (almost all) heavy metals and toxins (and several nutrients) down to it's barest form. People use this to know exectly what's in their water by adding it all back in themselves.

There is a BIG difference between the two in terms of what's actually going on with the kH.

In fact a better look at it would be the TDS (total dissolved solids) which in RO water is near 0 whereas you're not actually changing that number by acidifying the water with Co2.

I hope that helped rather than hindered.
 

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Discussion Starter · #3 ·
Thanks for your reply.
My post was actually more about the Carbo+ device itself than the CO2 addition.
Everyone says one of the bad things about Carbo+ is that it 'eats' the KH (which is how it generates the CO2) and I was wondering if this could be a good thing if one wants to lower the KH (regardless of the fact that the CO2 addition is rather poor with the Carbo+ unit).
I didn't pay attention to the difference between the two methods, thanks for clarifying the difference between this and RO.

I am trying to find reasons to keep my Carbo+ unit :icon_neut
or at least be able to live with it.
If it helps keeping a low KH, I would feel better about it. I bought it without reading anything about it and I am stuck with it now :icon_conf
 

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Discussion Starter · #5 ·
you mean my reason?
I have a couple of Apistogramma cacatuoides, 17 Neon Tetra, 2 Ancistrus, 9 Red Rasbora, 3 Siamese Algae Eaters and 5 white fishes (I don't know the name but they are literally white).
Most of these fishes tend to prefer soft water, and my tap water comes with around 9 KH.
a low KH would also help me keep a pH around 7 even with low CO2 addition.
 

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General Hardness (GH) would probably be more an issue than Alkalinity. KH (alkalinity) is just buffering capacity and has an affect on PH.
 

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Soft water means low kH AND GH. Reducing the kH with CarboPlus sounds good, but since you are not affecting the GH/TDS, I doubt it will be beneficial to your fish. Just an assumption though, based on the observation that the CarboPlus system is mostly considered wasted money around here.
 

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Discussion Starter · #8 ·
Thanks for the wisdom, guys :thumbsup:

Soft water means low kH AND GH. Reducing the kH with CarboPlus sounds good, but since you are not affecting the GH/TDS, I doubt it will be beneficial to your fish. Just an assumption though, based on the observation that the CarboPlus system is mostly considered wasted money around here.
Yeah, I noticed :icon_smil
It's really hard (who said impossible?) to find someone who likes this unit.
Fortunately, I just went to the shop that sold it to me and they offered to take it back at no cost two months after (except that I have to pay for a new carbon plate obviously) if I get a CO2 injection system from there.
Sounds like a fair and easy way to get rid of the damn Carbo+.

Regarding the GH, I'll check again and compare vs. tap water, but I think it lowered it a bit as well.

3 fishes died on me, not sure if it was because of the carbo+ unit.
1 Ancistrus (we didn't notice, we only found his skeleton in the tank, he was eaten), 1 Angel fish (couple days after the Ancistrus) and then one male Apistogramma Cacatoide 4 weeks after.
He suddenly started hiding and not eating, and 3 days after he was dead.
No idea why they died :icon_neut
The tetra neon are supposed to be fragile and none of them died.

I also suspect the Carbo+ to 'eat' the plant nutriments. Everyday I find 2-3 dead leaves floating around the filter, although the plants look quite well actually.
 

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Discussion Starter · #9 ·
ok I just tested again, with 5mL.

GH from the tap is around 8, and in the aquarium around 6.

So Carbo+ does affect the GH and not only the KH.
 

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from: http://plantgeek.net/forum/viewtopic.php?t=470&postdays=0&postorder=asc&start=0
It may effect the following reaction in hard water: Ca++ + 2HCO3- -> CaCO3 + H2O + CO2. The half reaction at the cathode is: 4H2O + 4e- -> 4OH- + 2H2 ... the half reaction at the carbon anode is: 2H2O + C -> CO2 + 4H+ + 4e- ... and the two secondary reactions are: at the cathode Ca++ + HCO3- + OH- -> CaCO3 + H2O and at the anode H+ + HCO3- -> CO2 + H2O.

The net reaction from combining these is: Ca++ + 2HCO3- -> CaCO3 + CO2 + H2O ... If the device is working right then it should generate CO2 off the carbon block. Some CO2 will also be generated by precipitating calcite, with a resulting drop in alkalinity and GH. The amount of CO2 generated from the calcite precipitation will be variable, depending on GH and alkalinity in the water, the amount of H+ and OH- that gets neutralized before the calcite is precipitated and the amount of calcite that gets redissolved after it's initially formed.

If the device is not working properly then electrolysis will still occur and the device will still evolve bubbles of H2 and O2, but most of the CO2 production will come from the precipitation of calcite. The amount of CO2 generated and the amount of calcite precipitation will be variable.
 

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Discussion Starter · #11 ·
Thanks, that explains what is happening.
The plate got dirty really fast in the beginning but now that the KH is low (around 3), the plate is getting dirty at a slower rate.
It also looks like it's producing somehow 'different' bubbles compared to what it did in the beginning, which makes sense when looking at the equations.

The manufacturer says the dirt on the plate doesn't harm the plants or the fishes, but the leaves near the plate died.

Anyway, I am giving back this damn unit, it's useless.
I'll just get a normal CO2 kit from Dennerle or JBL.

It eats the KH really fast. I changed 15% of the water on sunday which brought the KH back to 4, and 2 days later is was already back to 3.
I put some rocks as a temporary solution to increase/stabilise the KH.
 

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Thanks, that explains what is happening. ...
There is a lot of info about that gizmo on The Krib. I bought one of the damn things too. Heck, Karen Randall even recommended them. Steve Hampton tried a few of them. And the list goes on ... :hihi:

Anyway, I am giving back this damn unit, it's useless.
I'll just get a normal CO2 kit from Dennerle or JBL. ...
Before you get a regulator, that a look at the Victor thread. Quite a few of us are using two stage regulators and are very pleased. Two stage regulators aren't really required for our use, but they do work really well. We are finding them on ebay at very good prices and there are very good metering valves on ebay as well. Solenoids can sometimes be found as well. Then we are building them ourselves. If you have some patience, you can have a really nice regulator for not a whole lot of money.

Page 1 in the Victor thread has a link to various subjects.
http://www.plantedtank.net/forums/equipment/72328-victor-dual-stage-regulator-pimp-club.html
 

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Discussion Starter · #13 ·
thanks for the link and the hints :)
I had no clue about solenoids and two-stage regulators (or even 1 stage :)) before.

But I have to get my CO2 system from the shop, otherwise they probably won't take back my 2-months old Carbo+ unit :-(
They don't sell it in pieces and I have no experience at all for a DYI kit.
I know it will cost me more (or maybe much more) to buy a Dennerle or JBL kit (that ends up being not as nice as a two-stage regulator) but it would be an easier start, the package contains everything and you could easily add a proprietary pH-meter to control the CO2 injection. Perfect for beginners like me.

The DYI kit will be for my next tank :)
I am planning to get 400-500L tank in the mid-term, once I learn enough from the 180L I have now.


As for the thread subject, I guess the conclusion is that it could work to use the Carbo+ to lower KH/GH but it's nowhere as safe and reliable (or efficient) as RO, where you can get exactly the GH you want.
I won't have any regret bringing it back, it's not efficient in anything, and it's a pain to clean its mess bi-weekly.
It's all about perception... as a beginner, I perceived lots of complications and hassle from a CO2 injection system and this sounded easy and perfect and safe.
 
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