Algae Bloom

Kody Grieve

Member
Hi,

so my 100 gallon african cichlid tank is all fine and dandy until a couple of weeks ago when the water went green rather fast. I wasn't panicked because I knew what it was so I tested my water and went about normal routine maintenance. except I was quite surprised because my parameters were very good (ammonia 0, nitrate < 10, nitrite 0, pH 8.2) and the same as they always are, except now the water is green soup. anyway, my stand had slumped in the middle so a couple of weeks ago I completely drained the tank so I could put polystyrene sheets underneath to even out the weight distribution. so that was essentially a 100% water change. and within 2 weeks, boom. green.

who? what? when? where? why?

the only reason I can think of is that the tank IS by a large window and does get natural light, but if this is the cause, why hasnt this happened sooner?

do you guys have an answer or should I just buy a UV filter and fight the symptom, not the actual problem lol.
 

Mick Frost

Member
Natural light is a major factor. The timing is probably due to the time of year, with that window getting more light. Is it north facing?
 

TexasDomer

Member
How long do you leave the tank lights on?
 

TexasGuppy

Member
Do you have live plants? It could be that 100% water change reintroduced some (enough) nutrients to allow it to bloom, where normally, %50 or less, the plants are able to consume them before algae gets a foothold.
 
  • Thread Starter

Kody Grieve

Member
Mick Frost said:
Natural light is a major factor. The timing is probably due to the time of year, with that window getting more light. Is it north facing?
I'm in New Zealand and we are going into winter so no, less light than before.

TexasDomer said:
How long do you leave the tank lights on?
dont have tank lights yet

TexasGuppy said:
Do you have live plants? It could be that 100% water change reintroduced some (enough) nutrients to allow it to bloom, where normally, %50 or less, the plants are able to consume them before algae gets a foothold.
no live plants as it is an african cichlid tank and it was green before the 100% water change.

went green again within 2 days after 100% water change.
 

TexasGuppy

Member
What do you use for water? Isn't a pH of 8.2 high for cichlids? Are you using tap water? I'm guessing yes, it's likely your tap water has high phosphates and potentially other nutrients. I would add a UV and run Seachem phosfree in your filter.
 
  • Thread Starter

Kody Grieve

Member
TexasGuppy said:
What do you use for water? Isn't a pH of 8.2 high for cichlids? Are you using tap water? I'm guessing yes, it's likely your tap water has high phosphates and potentially other nutrients. I would add a UV and run Seachem phosfree in your filter.
8.2 isn't high for cichlids. perhaps south american cichlids but I have mbuna and haps so this is in their comfortable pH range. I am using tap water. however, I have always used tap water in my tank and it only just went green after I moved into the city (and subsequently into town supply) about 5 months ago. if it were phosphates, why hasn't it happened until recently? TexasGuppy
 

DuaneV

Member
Algae is almost always caused by too much light. If you know its getting natural light, then that's the problem. Any tank near a window will grow a ton of algae.
 

Vishaquatics

Member
I have had this problem before with my outdoor tubs. Here is how you can stop this, then prevent it.

To take the long but inexpensive way, stop feeding the tank so often and block out the natural light. Even leave the tank light off for a few days, but keep an air stone in there so your fish won’t get suffocated when the algae respirates. Eventually the green water goes away.

Now for the quick way, but can be expensive. Just get a UV light. Don’t get the algaecides because those haven’t had a positive effect on the health of the tank in the long run. When I was newer to the hobby and dosed algaecides, the green water became resistant to it after a while so it was a waste in the end. I recommend the SunSun or Green Machine UV lights. Replace the bulb every 6 months so that your fish don’t get electrocuted when the life and quality of the bulb is compromised.

To make sure the green water never comes back, plant your tank. Java moss, water wisteria, and jungle val are all great, hardy plants that suck up excess nutrients, look great (in my opinion), and provide a healthy habitat for the fish.
 
  • Thread Starter

Kody Grieve

Member
DuaneV said:
Algae is almost always caused by too much light. If you know its getting natural light, then that's the problem. Any tank near a window will grow a ton of algae.
I agree but why has it only just started going green when the tank has been here for 5 months? surely this would have happened sooner if it was purely due to natural sunlight

Koiman said:
I have had this problem before with my outdoor tubs. Here is how you can stop this, then prevent it.

To take the long but inexpensive way, stop feeding the tank so often and block out the natural light. Even leave the tank light off for a few days, but keep an air stone in there so your fish won’t get suffocated when the algae respirates. Eventually the green water goes away.

Now for the quick way, but can be expensive. Just get a UV light. Don’t get the algaecides because those haven’t had a positive effect on the health of the tank in the long run. When I was newer to the hobby and dosed algaecides, the green water became resistant to it after a while so it was a waste in the end. I recommend the SunSun or Green Machine UV lights. Replace the bulb every 6 months so that your fish don’t get electrocuted when the life and quality of the bulb is compromised.

To make sure the green water never comes back, plant your tank. Java moss, water wisteria, and jungle val are all great, hardy plants that suck up excess nutrients, look great (in my opinion), and provide a healthy habitat for the fish.
ok, that sounds like a plan, although there isn't tank lights on it anyway so I'm just going to have to keep the curtains closed.
and a UV bulb may be a necessity, considering I can't keep the curtains closed forever.
 

Vishaquatics

Member
Kody Grieve said:
I agree but why has it only just started going green when the tank has been here for 5 months? surely this would have happened sooner if it was purely due to natural sunlight



ok, that sounds like a plan, although there isn't tank lights on it anyway so I'm just going to have to keep the curtains closed.
and a UV bulb may be a necessity, considering I can't keep the curtains closed forever.
Yep, UV bulb never fails to do the job. But please remember that it doesn’t last forever and the bulb needs to be changed or it will electrocute the fish. I’ve learned this the hard way and lost even the hardiest common goldfish so please don’t risk it.
 

TexasDomer

Member
You can also paint the back of the tank black to block out the light, or move the tank away from the window.
 
  • Thread Starter

Kody Grieve

Member
TexasDomer said:
You can also paint the back of the tank black to block out the light, or move the tank away from the window.
the back of the tank is up against the wall and there's nowhere else for the tank as its a display tank. will just have to get a UV setup
 

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