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ok here goes.
Co2 setup planted 230 litre tank. tap water is PH 8.0 KH 11. with CO2 PH down to 7.0 now i WAS turning off CO2 at night and PH as expected was bouncing up to 8 by morning. since adding 4 Ottos to keep check on Algae i am too scared to allow PH to go up and down hence stressing fish (right?) so i have been leaving it running 24/7.
first concern- would turning airstone on for 2 hrs at 9pm (2 hrs after lights out) mean that im taking 100% of CO2 in water out hence then raising the PH anyway or would this not be enough to remove all CO2? as if it is removing all CO2 wouldnt it be the same as turning CO2 off?
second concern- is there enough O2 in water for my Ottos during the night and day for that matter? My filter is a Fluval 304 with a power head under the water surface to retain as much CO2 as poss without totally disturbing the surface water? there is a little water distubance but not enough to see O2 bubbles flowing though tank, only CO2 bubbles. how do i increase O2 without allowing all CO2 to evaporate due to too much surface water movement?? I ghess this is the most important question i would love an answer to.
Third concern- is a spray bar more suitable for my tank as the power head is not allowing some of the plants at opposite end of tank to stand up naturally but instead pushing them to one side with its current. maybe this was not the best choice of filter for planted tank but i ghess this is how we learn, through our mistakes. If id been on this site prior to buying the Fluval i wouldnt have bought it. Ive heard nothing but bad reports about this filter however at only 2 months old so far so good and it was able to remove all tannans from my 4 foot overnight! i was impressed anyway.
thankyou for all help given

loulou,

Here is my educated guess to your concerns:

For concern 1 and 2: If your ph increases over night by this much then you plant mass is not very large (right?). If right then that is the problem. Plants produce CO2 at night, maybe not as much as you add during the day but sure enough to keep a ph from bouncing all the way back up to tab water levels. You say, given that your KH measurement of 11 (that is in degrees, not ppm –RIGHT?) is right, that your CO2 level falls from over 30ppm during the day to 3ppm in the morning. That is a lot. Where does it go? Are you running that air stone already? I would say that your fish will show signs (swimming on surface and gasping for air) if there is not enough O2 in the tank. And instead of using an air stone (in this case, and only then) I would place the power head (or spray bar in the future) closer to the surface to create some small agitation.

Concern 3: I am not (yet) an expert on that matter, but I would assume that the spray bar is better as it distributes the water over a larger area than a single pointed power head. Neither nor will completely eliminate some current in the water that might lead to plant stem bending, it is more of a location issue than a tool issue. By this I mean that you should place fragile plants that you don’t want to “bend” in places that are less effected by the current.

Hope this helps,

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

1)The best solution would be a pH controller with electro-valve
2)The O2 in a fully plantet aquarium is enough. Fluval is OK, but EHEIM is the best...
3)Place the powerhead to the front of the Aquarium as we usually plant high reaching plants to the background... place the powerhead just below the surface in that it would just "steer" the surface (as you do with your soup!)

Last edited by Apostolis at 16-Nov-2005 03:11

ok, ive moved the power head up higher, so as to break the surface only slightly. now i can see some air bubbles circulating. i was running airstone for 2 hrs yes but now wont due to moving power head.
KH test kit i have measures in dH so my test showed it was 11 dH. my KH is not changing overnight just my PH. it says to reduce hardness to add deionized water or of course reverse osmosis water which the best i could do as far as the second option is water from our drinking water purifier. whats deionized water? is it distilled water? is it a good idea to mess with perimeters of my water? it sounds complicated and what about when it comes to water changes, would i have to mess around testing declorinated water and adding amounts of suitable water to get the same PH and KH??
this is my first real plant setup and the CO2 thing is completely new to me! I know a fair bit about what to do but didnt know about these proplems until they accured. I really want to learn but i ghess its a bit scary at first when i dont have anyone but you guys to help me. the LFS did not tell me about these probs accuring (typical) and i have lost faith in them now as i feel they miss led me in a lot of ways. they did not tell me my CO2 tank would only last a short time and that when i need to get it re-filled i need a second CO2 tank to replace the original whilst its not conected. so i have this prob to of when i took it to be filled by the time i got it back home (14 hrs) PH had gone from 7.5 to 8.0.
so with your answers, if the plants are producing CO2 at night, should i turn CO2 off or not? my plant stock is high but as there only new plants they have a lot of growing to do. so should i add more plants? i dont have much room left.

since reconnecting CO2 i must have ajusted valve slightly and increased bubbles per second as PH is 7.5
is my temp too warm at 27degrees? as weve had a few warm days and temp in tank has gone up a bit. shouldnt it be 26 or so. or 25? whats best for Ottos and future Tetras?

loulou,

Last question first: I think you tank temp at 27C is fine, although a little cooler could not harm (but don’t get it any hotter). My tanks are between 24.5C and 27C, in the summer months they even reach 28C for a few weeks in a row. The higher the temp the less Oxygen the water can hold.

You need a second CO2 tank? Maybe, I don’t – I found a supplier that is open until 9PM (a welding supply shop) and when I run out of CO2 I unhook the bottle, go there, get a new one, go home and hook it back up. I always have my CO2 disconnected (well, not running I mean) when I do tank maintenance, that that can take up to 6 hours these days (have you seen my 125G log?). I am not concerned about the lack of CO2 for that time period.

That is correct, your KH will not change over night, it usually stays pretty stable. I wonder what your ph is in the mornings, now that you removed the air bubble machine (). You say that you put the power head higher and it creates air bubbles in the tank – if that is right then it might be too high. Some ripples on the surface and surface movement is all you need.

Turning CO2 off at night – good question. Tanks go through natural ph swings during the course of 24 hours. These swings are gradual and usually not dangerous to fish what-so-ever. I would suggest (and I might be wrong here, so advice from others is appreciated) to keep the CO2 on for a little after the lights go off and to turn it back on a little before the lights come back on in the morning. Both ways maybe by an hour or so. BUT – this all depends what your ph is now in the morning without air bubbler. If it doesn’t go from 7 to 8 anymore, but rather to maybe 7.5, then I would say you could go ahead and turn the CO2 off with the lights. As your plants grow they will further enhance ph stability as they will produce sufficient CO2 at night, keep the progress monitored. Some here turn their CO2 off before the lights are turned off (their plants are tired, will explain some other time) and turn it back on to give the water a saturation head start before the plants will use it again (after lights on).

In general, don’t worry too much about your KH, 30ppm of CO2 are not bad, as long as your fish are not gasping for air on the surface.

Hope this rambling helps you a little,

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

thankyou thankyou thankyou Ingo [img src='/images/forums/halo.gif' border=0] it does help heaps, it tells me things are not as bad as i think. im learning all over again as i didnt realise how complex planted tanks where! and as for the CO2, well ive only just now got over being scared of the cylinder
I might allow my plants to grow some more first before reverting back to turning CO2 off at night. im getting proper lights with reflectors hopefully today as i dont see the point in me having spent all that money on CO2 with as i found out, 1 watt per gallon i feel really silly for believing all that the LFS told me as some of the plants they said i could grow are med/high light requirements. and they died. i will come here for advice now, you people are great and your input priceless
thanks again

loulou,

Thank you. Yeah, there is more to planted tanks than water and plants , but that is what makes it so exciting to me. Besides the fact how it looks, of course.

Don’t feel silly for believing the LFS, I tend to do the same. Sometimes they (or at least some of the guys there) know what they are talking about. They also have the problem that quite a few customers don’t care if something is good for them, they just want it anyways. This makes the store guys numb when it comes to giving advice.

Have fun with the new lights (what’s the data on them?),

Ingo

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Proud Member of the New Jersey Aquatic Gardeners Club

In case it helps, pH swings from CO2 are not as bad as previously thought. It is KH swings that cause problems, but do not worry about this because your KH does not swing. Like Little_Fish I think if your fish and plants are good so is your injection method.

One of my favorite aquarists grows many supposed soft water plants in KH >10 (buffered up for his Mbuna). Check out his tank here if you want -- sometimes he gets interesting color or growth and believes hard water might have something to do with it. Olive green Downoi (Pogostemon helferi), for example. Tom Barr also regularly disproves the soft water plant thing. Do not worry too much about messing with your water parameters.

You are doing great. Good luck.

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