I have a 25 gallon tank, stock lighting tank with dwarf Anubias, Ceratophyllums, Anacharis, Java Fern and Amazon swords. The trouble is that I'm seeing calcium carbonate deposits on anacharis leaves. I have a Ph of 8 and Kh of 3.5. I have no CO2 in the tank as per the calculator.

Although my tap water Ph is 7.5 and KH is 5.0 this fishless cycling tank has ph of 8.0 and kh of 3.5. How could the ph in the tank be higher than the tap water? I really want a planted tank because I feel my fish need the oxygen from the plants besides the surface agitation in the tank. Now I am caught with biogenic declacification from zero co2 levels if I add the plants and lack of oxygen if I remove the plants. Please help.....

You probably have something in the tank that is raising your pH. Any rocks? What kind of substrate? What sort of decorations do you have? I don't get the KH though, that seems awful low in combination with a pH that high. I have a pH of 8.2 and my KH is around 12 or 14 if I remember correctly. Check your test kits and make sure they are not expired or anything, maybe have a GOOD store double check for you if you can find one that does pH and KH and get numbers, not just "its fine".

I do know some plants, val's especially, can do something to your hardness, I think it was raise it, but I can't remember any details for the life of me...

I agree with Myaj. Now goldies will use some up on the kh, as will the plants to some effect.

What I do with my tank is this, I added in a very nice flex bubble bar along the back to help out. I saw some nice little round "spot" bubblers that would be cool to add in a tank even, they look like they'd be cute and certainly inexpensive to add. They offer those in two sizes.

In a planted tank, your pH will vary depending on what time of day you measure it. CO2 is an acid. Plants use C02 during the day and produce it at night... So in the evening, when you turn off your lights, pH will be the highest cuz there is little CO2 in the water. In the morning right before the lights are turned on, pH will be the lowest cuz there will be more CO2 in the water. Could you test pH first thing in the morning and again at the end of the light cycle and let us know what it's reading?


You could use Flourish Excel to add carbon that the plants could use.

Thnx all of u. My readings are right Myaj. It has happenned. I have biogenice decalsification. Which is why my Kh has dipped and have high PH. I saw white powder on my plants leaves.
Dataguru, my readings are PH 8.0 in morning and 8.3 at night. Though there is no color band for 8.3 I am assuming it between 8.0 and 8.5 after seeing the color. I am wondering how do people have a planted tank with PH 8 and KH of 7 or above when co2 turns zero?!!!!

I do not get Flourish Excel sadly...but if I have to look for a similar product what are the specifications I must watch out for. I get Sera products here mostly.

Myaj, do u have plants in ur tank. As per the CO2 calculator u have very low CO2 levels, 2mg/l. Dont' u also get problems with plants looking for alternative places to get CO2. for e.g. ur carbonates....
This is what happenned in my tank. i had a Ph of 8.5 and KH of 7 with zero CO2. My anacharis started taking CO2 from the carbonates leaving OH ions raising my PH really high. How do u handle it.

Dataguru, can u plz help me with ur earlier advise. I added the coral and raised the KH to 7.0 and ph rose also to 8.5. My tap water params are ph 7.2 abd kh of 4.5. Now when I change 70% water even when i raise the Kh of the new water to 7.0 the PH remains at 7.5. The tank ph remains at 8.5. This difference shocks them each time I change water which i do twice a week. As I understand the coral only reduces the swing in the already present tank water or is it fast enough to adjust Ph of the tank even after a 70-80% water change?

I do run DIY CO2 on one of my tanks, but only the one that has close to 3 watts per gallon. It doesn't make a huge difference but it does help some plants. It all depends on the plants you have.

The others don't really need it as they are around 2 watts per gallon or a little less.

I've never had any of the calcification issues you do though, other than hard water stains on the glass if I drip on it. Nothing on the plants.

I don't look too much into the chemistry of things as long as the plants and fish are growing and healthy .

Interesting. the coral shouldn't dissolve unless pH falls below 7.5.
How much light do you have over the tank?
Did you have any luck finding something like flourish excel?
How about a DIY CO2 generator?

I want to clarify what I said above, CO2 can make a huge difference, just with my size tank and the plants I have, it doesn't make a big difference in MY tank .

Dataguru, I am terribly suffering from swings. my ph never dips below 8 but does reach 8.5 during the day. So will the coral help. It is in the small tank right now. I can buffer with soda but again i land up with pH shocks during water changes.

i have a co2 dispensing system. Though it gives no clue how much to be used except to fill up the dispensing tube. ANd also not how often I am to use it. It si approx 5 inches in length and 1 inch diameter. Tetra CO2 optimaat. Myaj how do u measure ur co2 qty?

I dont get flourish excel. All other plant additives are with trace elemnts and none only as carbon. I have stock lighting. But the most imp. thing now are the swings. PH is 8.3 and Kh is 4.5. i have no decorations or stones in my tank that could rasie ph. Plain water, plants and fish. Java fern and amazon sword in glass votives. They look horrile with yellow brown patches and holes. I'm at a loss how Ph shoots from tap ph of 7.5 to 8.0 and above.

will my ordeal ever end?

I have stock lighting.
When the co2 is released is the effect on Ph instantaneous?

Like I said, I don't really measure mine. Mainly because I don't have any "difficult" plants. Mine is a DIY set up with yeast and sugar, and I just refill the bottle once a week so it keeps producing a steady amount.

I don't think either coral or baking soda will do anything for biogenic decalcification based on what I read last nite.

I think the CO2 takes a while to build up in the water. Depends on how fast it's running, how well it's being diffused into the water and how much surface agitation is happening in the tank to gas it out of the water. You can estimate how much is in the water from your KH and pH levels. Here's a calculator/

The other option is to remove the plants that are able to extract carbonates from the water. Not all plants can get their carbon from bicarbonate. I remember reading that anacharis/elodia can. Which plants have the calcium deposits on them?

yes. thats what I did. removed the anacharis and ceratophullum. still have the anubia, java fern and amazon sword inside.

I did not mean that baking soda caused biogen. decal. but what I wondered was if there was a way to go about soda without the fish having to go thru shocks. I see the same problem persisting even after I transfer them to the bgger tank - the ph swings I mean.

sorry, i keep forgetting things. I have one air stone in the 5 gallon and none in the bigger. I checked with the calculator yesterday itself after I releasesd the co2. there was no change in the ph or kh which is why i asked. [erhaps it got used by buffering. but the next shot shld dip ph suddenly.. could i be right?

I saw the salt on anacharis, ceratohyllum.Actually sisnce my bigger tank is still cycling I am experimenting there. But the smaller tank is really haviing swings all over again.

Ok once I raise the Kh with soda in the smaller tank and put the coral in there u sugest that I dont need to add the baking soda in each fresh water change in order to match it to the tank KH. The tap water shld get adjusted to the tank params thanx to the coral except if I do a 70% water change right?
TAP PH 7.5 ; TANK PH 8.5
TAP KH 5.0 ; TANK KH 4.5

The next shot?
Isn't the CO2 continuously bubbling into the water?

Hmmm, I think it'd stick to smaller more frequent partial water changes in the 5 gallon. That should affect pH less. I don't think you need to buffer with baking soda give the KH is so similar. I'd think your pH should gradually get lower in the 5 gallon now that you're adding CO2 and have removed the plants that were causing the pH increase.

Any idea how long till the larger tank is cycled?

The CO2 apparatus goes like this. It is a vertical tube with a membrane on top. The water gets filled in the tube when i insert it into the tank. It gets attached to the wall of the tank with suction caps. There is a pipe that connects the tube to the gas cylinder. When I press the nozzle of the cylinder the water level in the tube inside the tank goes down as the tube gets increasingly filed with the gas. The gas goes out of the membrane on top in a matter of half hour tops. In essence the gas gets released in the tank in half hour flat. No continous bubbling. Sounded weird to me too. I released it for the 2nd time today. PH has marginally come down. Its so hard matching colors so often I am beginning to suspect I'm colorblind. its between 8 and 8.5 I think.

I have been seeing ammonia in the larger tank now for days and no sight of nitrite yet. I think the swings shld not be so bad once they enter the bigger tank. I just read ur ammonia thread. It's so coooool. Loadza info. One thing I learnt was the overstocking seriously leads to ph swings no matter what. isnt that so? Duchess has a huge split in her tail. The others are looking bad too. I will wait for one more week. If it gets too bad. i think i will just put them in the bigger tank and cycle with the fish. Its been up and running for a while now. what says you????

Dunno...If you moved your filter, gravel, etc into the larger tank, I'd think it would be almost cycled given that it's handling the fish load now in the smaller tank.

Can you adjust the CO2 valve to where it's releasing a slow stream of bubbles? Usually CO2 is a continuous flow thing. Now that you have the carbonate stealing plants out of the tank, patrial water changes should get your pH down without having to dink around with CO2.

the larger the fish load, the more carbonates are used up converting the ammonia produced to nitrAte. So over time if your water isn't high in KH, pH will get more acidic. Plants will give you a daily pH swing cuz of CO2 use/production.

I had removed the anacharis and ceratophyllum from the small tank some time back and have done several changes since. I saw the same thing happening in my bigger tank too. But in the smaller tank the Ph has continued to remain high. When I had put in the coral the first time I had a gush of suspended dust in the tank. Could that have settled at the bottom and causing the PH to be steadily high?

The CO2 sadly has no adjusting valve. But I checked the PH again today morning and it is at 8.0. Hasnt dipped.

I have been reading a dutch aquaforum and most have KH as low at 3-4 and ph at 6.5-7.0 with tropical and amazon fish. And not one post I read of ph swings. And dutch aquariums are heavily planted. I wonder how.

The coral shouldn't dissolve unless pH falls below 7.5. so no, the coral dust shouldn't be increasing pH.