"Green water" ===>problems?

[Ichtyus]

I had posted about the subject 2 days ago (before the new forums) to say the following:

A friend of mine has a 25g with 5 cichlids in it. Fish seem comfortable. pH is ~5.6 and water is clear. Tank has been going for a few months (I assumed cycled by now). However water is now emerald green. What's the problem?

I got a reply from TheMightyQueenPixie:
1- is pH 5.6 normal?
2- what kind of cichlids in tank?
3- green is probably and algea bloom due to overabundance in nutrients in water.
4- redirected me to a link at http://www.skepticalaquarist.com
5- suggest water change and "light starvation" for 5 days

I also got a reply from TnCgal:
1- welcoming me to the forums yeah baby!!
2- low pH is not usual for cichlids, recheck
3- what is pH of tap water?
4- any medication used recently?

Wow, a lot of advice and things to do...
BTW the 5 fish are 1x jack dempsey, 2x salvini, 2x convict

Here's what I did up to now:
1- read the section on green water in the link: quite good and informative
2- asked friend about feeding habits: fish are fed once daily (doesn't sound too much to me, but suggested to feed every 2 days)
3- tested carbon content in waste water from water change:
approx. 2ppm inorganic carbon and 12ppm organic carbon
4- suggested "light starvation" = cover tank with towels 5 days
5- tested pH of tap water: 7.47

will get sample from tank after water change for pH. I am testing carbon content in tap water (is that of any help?)

any comments?

 

[wetmanNY]

If the pH of the tapwater is 7.4 and it's truly dropping to 5.6 in the tank, then there are a lot of organics being pumped into the system, and the alkalinity or carbonate buffer is being overwhelmed.

Things to get your lady to do:

1. Increase the partial water changes.

2. Rinse out the filter media every four or five days for a while, using the siphoned-off tank water-- that way she won't harm the nitrifying bacteria. The "gunk" in the filter is being broken down, which releases more CO2 into this CO2-stressed system.

3. Drop the water level to get more "splash" from the return. This increases the rate at which CO2 is outgassed.

4. Does anyone have a clear fishfree planted tank who'd give you a gallon or two of water, along with its freshwater plankton? The plankton may be a missing part of the system: the microscopic critters that graze the green algae and euglenoids that make the water green.

5. Get floating duckweed and boost the light intensity. Those cichlids will munch on duckweed a little, which is good, but they'd trash rooted plants. Keep collecting it in a net and throwing it out. Keep about half the water surface covered with duckweed. This shades out the green water and competes with it for nutrients and leaks allelopathic chemicals perhaps too.

6. Put the lights on a timer. No more than nine hours a day.

 

[Ichtyus]

Ahh good advice wetmanNY, I think you have put your finger on part of the problem: she does not rinse out the filter sponge regularly so I think it is possible that there is a buildup in there being broken down (which would explain the 12ppm of organic carbon)

Didn't think about the outgassing of CO2 with increased splash, good idea!

I will see if I can get someone with a fish free planted tank to get water from.

She does have floating plants, don't know how much, will look into that. Is duckweed a name that will be recognized at the pet shop?

her light is on a timer but I don't know for how long.

what are allelopathic chemicals??

 

[TnCgal]

Allelopathic chemicals are transferred from one plant to another in order to inhibit growth and germination.

In Wetman's post, he is suggesting that the Duckweed will outcompete for nutrients, perhaps releasing allelopathic chemicals to keep green algae at bay.

 

[ewok]

for some reason i have this feeling we are skipping the obvious here......

how *big* are the 5 fish? cons usually max around 4", jd.. 6 or 7" i think, salvinis... i think about the same as jd's..........

what has the maintenance been like? how often for waterchanges and how much volume? how often for vacuuming?

i am not argueing with what anyone else posted, just thinking this may be a case of too much fish and not enough waterchanges..... basically overstocked for the volume of water. this creates a decent amount of waste, dumps the ph hard like it is and sends the nitrates through the roof in a well cycled/cycling tank......

strictly conjecture, and again, i am not argueing with advice already posted, but i would suggest also (slowly) increasing the volume and frequency of waterchanges and vacuuming. it sounds like a heavy fish load to me, and this is the exact same thing that happened to me when i overstuffed a tank, except the algae which i never got. you do not however want to go out and do 50% all at once as your ph is too low to begin with, if you do anything to radically alter your ph in a short period of time you can shock the fish to death.

i would suggest doing 10-15% water changes basically every day for the next week to slowly increase the ph, and then maybe a big water change or two ( 20-30% ) ......... and then do the 20-30% weekly........ (also use dechlorinator of course) this should slowly acclimate the fish back to the normal tap ph, get rid of some nitrates, and somewhat dilute the algae at least.

also i would increase the vacuuming of the substrate (maybe once a week?), decaying matter will add to the problem as already noted.

forgive me if this is re-covering the same ground........

 

[wetmanNY]

Originally posted by ewok
... you do not however want to go out and do 50% all at once as your ph is too low to begin with, if you do anything to radically alter your ph in a short period of time you can shock the fish to death.

Good point! Now, there's a point we haven't mentioned: at pH 5.6 just about all the ammonia is in its harmless ionized form (NH4 instead of NH3). As you do things to raise the pH to a more neutral level, the ammonium NH4 will convert to toxic NH3, resulting in what we think of as "pH shock." If you had even a trace of ammonium, this could be very stressful.

 

[Ichtyus]

Agreed on these good advice.

Fish size is: convicts approx 1.5in each, jackdempsey 3.5in and salvinis 3in each. Water changes of 25-30% are done 1/month and sponge is cleaned at time of water changes.

One thing though, if this is a cycled tank then there should be enough bacteria to ensure that the ammonia produced is rapidly changed into nitrite (or am I assuming too much? this could be a good discussion subject...)

However a few things have happened since...

She had done a 20% water change and then covered the tank with two towels...and here starts the nightmare... One of the towels somewhat flopped below the outake of the filter, got wet and... started to drip on the floor (capillarity helping) and she lost 2 inches of water by the time she got home from work with a huge puddle of water on the floor!! The tank is on a wooden stand that was by then getting wet. So she empties half of it to be able to move the stand and dry everything as much as possible then refills it. So now we have a major water change! I have no idea how the fish are handling it, will find out on monday.
However, for now the towels for "light starvation" are out of the picture!! and the "green water" is not a priority.

Did test the carbon content of the tap water and found approx 3ppm of organic carbon (I forgot the exact figure and the inorganic carbon content, will post the numbers on monday). Also tested the carbon content of the water in the tank after that initial 20% water change, it went up to approx 17ppm

So the plan is to watch carefully the fish over the weekend and we will test the water again on monday and hope they make it.

Two question here though, why would that be too much fish for the tank? isn't the general rule 1in per g? I have a 25g tank with 3 breeding pairs of pelvicachromis pulcher (kribensis) and 4 young ones, all with vibrant beautiful colors. They do tend to chase a bit (lack of territory space) but they don't seem to suffer. Have given already 4 breeding pairs and they are doing quite well in their new homes. They've been breeding like crazy (stared with one pair, everyone else is from them ) I just love watching them taking the little ones for feeding excursions . Mind you there is no breeding now until I get most of them out of there: no privacy to do the mating dance, LOL.

What are your opinions on vacuuming? I tend to do that 1/2-3 months personnally as I find it stresses the fish. Am I in the wrong? I don't think she has vaccummed the tank for a few months either.

 

[TnCgal]

ichtyus,

What is happening in your tank is this :

1. You are overstocked. The 1 inch/gallon idea is a misconception that has been floating around the hobby since the beginning of time and grossly inaccurate. It doesn't take into consideration the demeanor/type of fish and once you talk about breeding pairs, it renders the entire theory null and void ... especially three breeding pairs. I'm not trying to come down on you, but if you have 3 breeding pairs of cichlids in your 25g tank, you are asking for trouble.

2. Your vacuuming regimen needs to be stepped up big time. The accumulation of waste in the water will drive the pH downward in an acidic direction and destabilizes the water putting your fish at risk for diseases and death from a number of bacterial infections. Keep in mind that your filter will not eliminate waste out of your water... waste will liquify and is kept cycling over and over again in your water until it reaches dangerously toxic levels. There are harmful bacteria that feed on waste products in the water and a fish that is stressed (from overcrowding for example) can easily succumb to any number of diseases. This might also be the cause of your algae dilemma since algae will grow where there is an excess of nutrients present, which in your case there are, in the form of waste products.

My advice to you is :

You will want to eliminate most of the fish in that tank. For a 25g, I would never recommend more than 3 or 4 breeding Kribs in the ratio of 2-3 F/1 M. I would either find a bigger tank to house the rest or take them back to the fish store. Keep in mind that your overcrowding problem will likely be solved by the fish themselves if not by you.

Do 30% water changes every other day until your pH is brought under control, vacuuming every time. You should never forego cleaning their tank in lieu of stressing them... they get used to it, trust me. Living in a cesspool of detritus is far more stressful.

Make sure your filter pad/cartridge is cleaned or changed at least once a month to eliminate solid waste accumulation and to decrease risk of harmful bacterial growth.

This situation can be undone but it will take a little work. I'm just glad we caught it before you started losing fish ! Good luck !

 

[O-man21]

I agree that you are over stocked and you ned to clean it more

 

[Ichtyus]

Thanks all for the good advice, I shall follow up on it!

Some work has already been done (water changes) and I will have to give some of the fish away from my tanks. My friends tank seems to be on the right track, pH is now 7.8 and no green color. I will let her know about this overcrowding situation which she also has.

Question for you guys though. I have now 3 tanks going but had to move two of them in the basement (my kids are growing and need the bedroom that I had dedicated to my tanks. Therefore I want to close 2 of the tanks and only keep one tank going (33g). I have a pair of melanochromis johannii, a male cichlasoma nigrofasciatum, 10 pelvicachromis pulcher and a trichogaster trichopterus. I was planning on keeping the pair of melanochromis. What of my other fish would you suggest I keep with them? I am not interested to get some other fish (from pet shop) since my goal in the medium-long term is to get a somewhat bigger tank and get a pair of symphysodon aequifasciatus.