Help with cyano/BGA and tank levels!

[Puddle]

I have a 40 gallon fairly heavily planted tank with some driftwood that is now about 5 months old, and I can't stay on top of a BGA/cyano problem , I did have other types of algae (hair/beard) but they seem to be going away to levels I don't mind since introducing rowaphos as the phosphate levels were terrible from my tap water .

My CO2 is 12.1ppm, KH 16 (I think - from memory!) and phosphates below 0.25, nitrites 0 and nitrates between 0 and 10, pH of 7.6.

I have 10 cardinals, a few guppies and a lovely SAE with the intention of getting more fish soon as lots of space. I did add a liquid fertiliser once a week as directed but thought it was making it worse, but not so sure now after reading the forums! Any help/suggestions would be greatly received! Thanks

 

[rich311k]

The BGA is from your low nitrate levels. BGA will also grow in areas with low flow. How much light do you have? Do you add any kind of ferts?

 

[Puddle]

Thanks - What sort of levels should the nitrates be at? I think the flow isn't too bad but it definately starts growing first (every time I remove it) on the lighter coloured gravel I have so maybe should change the flow direction - Will find out the lighting levels, not sure off hand but the lights are on for about 9 and half hrs/day? Only liquid ferts for the plants with trace minerals.

 

[7Enigma]

10ppm nitrAtes is a good target to shoot for. I prefer to keep mine ~20ppm just to be sure, but it all depends on your fish and bioload.

 

[rich311k]

We really need more info. Light, tank, bioload, size etc. Do you inject CO2?

If you have BGA chances are your Nitrates are low. test kits are pretty much useless under 20 ppm. Without knowing more it does sound like you need to start adding the macro nutrients. What kind of liquid fert are you adding?

 

[Puddle]

Hi
Tank is 40 gallon, have 2 x 30 watt lights which are on for 9.5hrs/day, don't inject CO2 (a new concept for me!) - I'm quite new to the finer points of fish tanks! Just re tested water:

NO2 0mg/L
NO3 10-25mg/L
KH 6 d
pH 7.6
Phosphate 0.5mg/L
= CO2 of 4.5ppm

The only liquid i add at the mo is one with trace elements Magnesium, Mangane, Flouride and Potassium?

 

[Purrbox]

What brand of test kit are you using and have you calibrated them?

Welcome to the forum BTW!

 

[Puddle]

Thanks!

Using Tetra test strips and nutrafin PO4

 

[Purrbox]

Test strips are best only used to give a quick ballpark idea of the levels in the tank as they are notoriously inaccurate. The Hagen Nutrafin test kit is a reasonably good test kit, but should be calibrated against a reference solution to determine how accurate the results are. Unless you are willing to buy better test kits to replace the Test Strips and calibrate them, the results shouldn't be used to base your dosing on. They can give you a general idea of what the problem might be, but you'll have to use the plants and algae as indicators of what is going on and how to correct.

You've got a low to medium low light tank. Based on this you'll probably need to dose a good trace fertilizer like Flourish (Comprehensive), Tropica Plant Nutrition, or CSM+B along with Potassium with KCl (No Salt), or K2SO4. Based on the symptoms you are seeing in the tank, theres a good possibility that your tank is fairly lightly stocked compared to the amount of plants which means that you'd need to dose Nitrate with Flourish Nitrogen or KNO3 and Phosphates with KH2PO4. Since it's a low light tank you'd probably only need to dose once a week.

 

[Puddle]

Whats the best way to calibrate the PO4 kit? My plants seem to be ok, they're not really dying but I wouldn't say they were flourishing either! There are a few odd brown leaves though. Also have the BGA and some longish (~5cm) dark green/brown strands of algae as well which are growing on the top of the rocky back structure I have.

I have about 22cm of fish in the tank at the moment so is probably quite lightly stocked.

 

[Purrbox]

To calibrate any test kit you'll need a series of reference solutions. You can do this by mixing them yourself using a fert calculator, or they can be purchased. You then test the kit at several key levels and determine how far off you test kit is off. You can then adjust your test results based on this infomation to get true values.

Part of the reason that your plants aren't doing much, is that you don't have a lot of light. This makes for a tank that is much easier to care for since it doesn't change very quickly. Once you get your ferts balanced you should see some increase in growth, but nothing super dramatic.

I would say that it would be a good idea to go ahead and start dosing once a week, right after the water change on the weeks that you do one. For now I'd probably dose 10-20ppm Potassium, 10-20ppm Nitrate, and 2-4ppm Phosphate. I'd also dose enough trace to get 0.1-0.2 Iron (fe). Go with this for a few weeks and see how things are going. You can then adjust up or down as needed. Once your tank is more heavily stocked you'll probably be able to back off on the Phosphate and Nitrate dosing.

 

[Puddle]

Thanks for your continued help! I was told that phosphates increase algae growth, I have quite a high amount in my water, its very hard water so I decreased it using RowaPhos.

Should I be worried about the low CO2 levels?

Is it worth doing a black out to get rid of the BGA in the meantime?

What are the ideal levels to be aiming for in the long run?

Sorry for all the questions!

 

[Purrbox]

It's a common misconception that Phosphates cause algae. In actuality Phosphates is one of the nutrients that plants need in order to be able to grow. In a non planted tank you want to minimize ALL nutrients including Phophates to prevent algae growth. In a planted tank if you have too little of any of the nutrients that plants need, the plant growth will slow or halt and algae will take over. The particular type of algae will depend on what is in short supply as each algae will thrive under different circumstances. Low Phosphates will usually result in Green Spot Algae, but can also result in other algae as well.

You may have enough Phosphates available if you get rid of the phosphate remover.

You don't have enough light to require the need for CO2 injection in your tank. While CO2 injection would help plant growth you don't NEED it. As long as your CO2 levels are consistently low you shouldn't have any problems. Also please note that you can't use the standard pH/KH chart to determine your CO2 levels. Your water has another buffer present that is throwing off the relationship. Right now your water only has about 3ppm of CO2 despite what the chart is telling you because you aren't injecting CO2.

A blackout is worthwhile as long as you fix the problem that is causing the BGA at the same time. If you don't fix the underlying cause, the BGA will just keep coming back. So you'll want to start your dosing and then commense the blackout.

Ideally you want to have enough nutrients in the water so that you don't risk bottoming anything out. The amount that you need to dose varies from tank to tank based on the setup and the type and quantity of plants. Some common targets are 20-40ppm Nitrates, 1-4ppm Phosphates, 10-20ppm Potassium, and 0.1-0.2 Iron. To dose to the targets you would need to use calibrated test kits from Nitrates and Phophates. There aren't any reasonably price kits for Potassium and Iron, so it's best to just dose based on plant health. They'll tell you if you need more.

There is a link to a thread on Fertilization in the Read this First Sticky that would probably be helpful.

 

[Puddle]

Thanks once again, its been very very helpful!

I will try to get some decent fertiliser and do the black out to have a fighting chance from the start! I am in the UK so was wondering if anyone knows of a decent fert available here? Or suppliers for the nutrients?

At the moment I have the following plants plus some others I'm not sure the name of(!)- any better plant suggestions also gratefully received:

Amazon Sword
Augustifolia
Dracena green
Java fern
Pigmy chain sword

 

[Puddle]

Just to let you know I did a blackout for 5 days, started dosing ferts and to my joy I haven't seen the BGA back for over a week which is great considering it was there everyday! Also all the other types of algae that were present in small amounts is gone too, yay, so thanks for all your help guys! Fingers crossed it stays away!