problems with turbidity & filmy grey/black algae

[frog girl]

Hi I haven't been here in a while but I see some familiar names.

I am hoping you can help me solve 2 problems I am having. The first is a turbidity problem and the second is a filmy black/grey algae.

MY TANK:

70 gallons filled to 55 only hexagonal

age - 4 years

substrate - clay and vermiculate topped by a layer of sand & gravel

latest water chemistry (in general it has been very stable)
pH = 8
ammonia = 0
nitrates = 0
GH = 6
KH = 6

decorations etc - 2 pieces of drift wood and a small piece of limestone for buffering

water source - DI drinking water from our in house system
change about 5 gallons once a week (10 if the tank is really dirty)

lighting - 4 compact flourescent full spectrum bulbs
I don't rememberr the WPG but suffice to say that I am on the lower edge of a well lit tank and get pearling if I add CO2.

filter etc. - hang on the back 50 gallons per hour & a power head to keep the rather deep tank mixed enough

feeding - zuccini every 1.5 weeks and a pinch of flakes once or twice a week & all the algae they can eat

PLANTS - 5 largish bunches of java fern
1 large sword
2 melon swords
2 large crypts + small offspring
5-6 small crypts & counting
a bunch of anacharis
a bit of water sprite
lileopsis carpet in the front where there isn't shade from the big plants
also a lot of types of algae which my fish generally keep mowed down

ANIMALS - 1 tiger barb
3 otos
5 rasboras
5 rosy barbs
1 rubber lipped pleco
1 SAE (yes I am sure its an SAE)
a few pond snails (the fish eat the babies & I squish the adults)

A BIT OF HISTORY
I was having trouble with BG algae hanging on so I treated it and bit the bullet with making PMDD. I order my chemicals from gregwatson.com and followed his recipe. For 2 weeks I dosed the recomended amount and then doubled the nitrate as recommended for heavily planted tanks.
My sword, crypts, and lileopsis all made lots of leaves and I was happy.

PROBLEM 1
This grey/black algae appeared that is the texture of BG but doesn't smell bad. Also it grows in lumps and strands. I got my SAE to see if he would work on it but it is not favored among any of my fish. They like green algae better but it is starting to get a bit scarce in the tank. I have seen the otos, tiger barbs, SAE, and pleco all work on it a bit and sometimes the barbs really go at it and clean something off. I tried reducing my fertilizer but it just knocked back the green algae and the black filmy stuff just keeps on going. Its just like the energizer bunny except I can't figure out where the energy comes from. In one day it will double or triple in size while the rest of the algae languishes. Any ideas??

PROBLEM 2
In the morning when I wake up the tank is perfectly clear but within the hour of the lights coming on it takes on a green tinge and gets hazy as if I had unicellular algae. It never gets really bad I can still see 12-18 in. or more. Then in the evening before the lights go out the water starts to clear up again. Sort of weird . . . Thoughts??

POTENTIAL SOLUTION
I am no longer doing CO2 because it is a hastle to do DIY and I don't have the $$ to get a pressurized system. Could CO2 be the limiting factor? If so my choices are BG algae, black/grey algae and turbidity, or biting another bullet and going back to the CO2.

Thanks for reading all this. I wanted you to have all the info.

I hope you have some advice for me,

Kate

 

[czcz]

Hey Frog Girl! I think nitrates at 0 means the dosing must be tweaked to solve problem 1/BGA. How often are you dosing PMDD? Can you test for NO3 after dosing? Do you add any PO4 besides feeding? Suggest you dose to 10ppm NO3 and measure how long it takes to drop. Having NO3 available will prevent BGA, but lack of any other macros (P) will still allow algae to outcompete plants.

By "lower edge of a well lit tank," do you mean low-med light or med-high light? Problem 2 is interesting, and I wonder if it happening in the daytime is related to too much lighting. Have you tried lowering lighting? Is there sunlight hitting the tank?

I think if you black out to treat BGA, then dose N while lowering light, you can get a jump on both problems at once. I do not subscribe to PMDD and so think you should investigate phosphate levels and dosing, as well as K/potassium if you do need to dose much KNO3 to maintain your 10ppm NO3 target. HTH. Nice to read your username

 

[frog girl]

Hi back at you czcz.

Actually I am pretty sure that the weird black algae is not BGA. It doesn't smell like it and some of the fish eat it. I did have BGA problems but I treated it with black out and antibiotics & so I currently don't have any. I decided to start fertilizing in order to reduce the chances of a new infection since I got infected twice over the span of several months. I know higher NO3 levels are supposed to help.

I was doing the daily dose of PMDD but recently I have been doing it only twice a week to see if it is the fertilizer that is making the black algae go crazy. So far less PMDD doesn't seem to have much effect. I haven't tested for NO3 right after dosing but I will if you think that will help.

I don't had P except for feeding because I have always read it can cause really bad algae blooms. I will have to read about it a bit.

There is no sunlight hitting the tank and I haven't changed the lighting at all. Some other factor must be causing the change. Reduced lighting might help the turbidity but I don't really want to majorly reconfigure my aquarium (I like my plants). . . My question is how can the one celled algae be getting along when they have so much competition?? My WPG are about 1.5.

I can't imagine ever being able to truly maintain the 10 ppm NO3 target. I think my plants suck it up as soon as it hits the water. I have tested several hours after fertilizing and there is nothing there but I haven't checked right after.

Thanks for your advice. I will check NO3 levels right after dosing tommorow and report back.

 

[czcz]

It may help to test nitrates after adding known concentration, just to know if the test is acting funny. A rounded half-teaspoon of dry KNO3 should get the tank to around 10ppm NO3. (.5tsp raises 55gal ~8ppm.) If it drops back to 0 by night time, I do not think it is out of line to dose 15-20ppm NO3 3x a week, considering your bioload, even with low-med light. Are your plants growing well?

I find the hazy water problem interesting. Agree - I do not think you need to lower from 1.5wpg. As you know, plants are dependent on all macronutrients, including P, and will stop uptaking and growing with macronutrient deficiency. Single-celled and low order algae are then able to capitalize on any nutrients left. While low light tanks generally do fine with no P dosing, I cannot help but wonder if the relatively low fish stock and fast N uptake means there is certain P deficiency. I follow the mindset of The Estimative Index because it makes sense and works for me, and so would feel comfortable dosing P in moderate amounts blindly. I would probably dose .5ppm, observe, and dose more if warranted. If this ends up helping, we can help you to readjust the mix to go back to PMDD-style dosing.

Perhaps a change of filtration media will lower turbidity though, considering the water clears so quickly in this case.

I recal reading there are many types of cyano that fall under "BGA," and am still inclined to think your film is one of them, but am no expert.

HTH,
Joe

 

[frog girl]

Joe,

Most of my plants are doing fine. There a couple crypts which need substrate fertilizer but everything else is producing leaves. I would say there is medium not rapid growth compared to other observations but I thought this could be because there is black stuff on many of the leaves. I had the best growth when I have CO2 running and was using premixed fertilizer. I will test my NO3 test to make sure it is working and then watch how fast it disapears in a controled way. Tommorow is supposed to be cold here so I won't be working outside much.

Maybe the algae is cyano it certainly has the right texture. I will look around for some P to see if that helps after I look at the NO3. Even if it cause an algae bloom as long as its not cyano my fish should gobble it up. I will also read about the Estimative Index. I am essentially doing PMDD without testing my iron levels and just going by the general guidlines given in the website. My funds are a bit low so I haven't even looked at iron tests.

Thanks a bunch for your help. I may e-mail you later if I get funny results or just to report in.

Have a good weekend,

Kate