Contradictory Advice

[Spiceweasel69]

I have brown algae and hair algae in my tank. I have ordered some flourish excel to kill off the hair algae and for use as ferts.

The brown algae i thought was caused by excess light - having read through lots of articles, many say it is due to insufficient light?

Im confused.

My phosphates are at 5ppm, Ammonia 0, Nitrite 0, nitrate 5 ?? (too low i think) running 2.5WPG in a 600l tank however have only been using half this for the past week since algae appeared. Have bought several cabomba to soak up any excess nutrients and 6 ottos to combat the diatoms. Will perform 50%wc today as the phosphates are too high as i think i overfed a few days ago.

Can anyone suggest what i should do to stop the algae?

I have co2 injection but am still waiting ceramic diffuser and drop checker from malaysia. JBL test says co2 level is OK, so i guess thats about 25-30ppm

 

[RadaR]

The 5ppm of Phosphate is fine.
Brown diatoms is caused by ammonia, (concentrations that are small enough to go undetected on a hobbyist's liquid test kit, hence why your test kit will say "0", when in fact it actually isn't).
Just scrape it off and Otocinclus will eat it. Introducing the Otos was a good move, as was introducing fast growing plants to consume some of the ammonia. Water changes will help to, not to mention hovering up any decaying matter in the tank/filter.
In the long run, 5ppm of Nitrates is too low. This will have to be increased via Tropica Plant Nutrition + or potassium nitrate powder.
The Excel will help provide carbon to the plants, yet without the drop checker with 4dkh solution and bromo blue reagent, I am skeptical whether you've got enough carbon dioxide being dissolved into the water.

 

[SuperColey1]

No algae is due to the light being too high. Nor too low within reason.

Algae grows when the nutrient (including C) is not sufficient for the light given.

Nutrients is very easy to rule out. Add too much and there can't be a defficiency. CO2 is the harder because you can add too much even in a fishless tank but it is hard to get it to the plants with it being a gas.

Many people think they are already adding excess of both and indeed they are. The problem is that they have poor flow/circulation and therefore the excess they are adding is not getting to where it is needed. This is why some areas do well and others not.

Thats why we suggest getting filters with ratings at least of 10x the tank volume per hour. Some of us go further and add Circulation Pumps meant for marine tanks to boost the flow circulation right up.

Mine for example has a filter of 5.6x and a pump of 12x making 2200lph on a 125ltr tank. If you check out most people who go with high turnover like this you don't see much algae

In summary I would suggest your CO2 is low either because it is not being injected at a high enough rate or the circulation is not carrying it around enough. I would also say Excel is not going to provide much in the way of ferts. If you want to go thebottled route then you need the whole Seachem Nitrogen, Phophorus etc range otherwise you can research a little into EI dosing (Estimitive Index) which is much easier and cheaper.

AC

AC

 

[Spiceweasel69]

I have looked very thoroughly at EI dosing (even bought the ferts from aquaessentials) but i cant spare the time every week to change the water - i can do 50% every 2 weeks, but i cant guarantee every weekend. I am currently running a fluval fx5 and a 1200lph powerhead so the water movement is pretty good.

Diatoms have reduced, dut to the ottos methinks. Slowly it is being replaced by green algae.

When the drop checker arrives ill get hold of a 4dkh solution and get a real idea of how much co2 is in the tank. The nitrates are far too low in my opinion to sustain a heavily planted tank so i will make up a mix and dose later on.

Cheers for replies.

 

[SuperColey1]

Then remix your ferts and use the PMDD+P method with 10-20% water changes:

http/www.theplantedtank.co.uk/PMDD.htm

AC

 

[Spiceweasel69]

Thanks -looks perfect.

 

[Spiceweasel69]

Also as a quickie - i have a small piece of stone that i believe to be some form of limestone as i took a similar piece out and dropped vinegar on it, and it created a few bubbles. My PH is 8 which would corresond with raised alkalinity from the limestone.

Going on the co2 / KH / PH calc, if the PH is higher, the less co2 is in the water at any given KH. Question is, will the limestone be detrimental to the amount of co2 in the water (will it drive out the co2) as it raises PH, or will the KH change to compensate and the co2 ppm remains a function of the injection rate??

 

[plantbrain]

Otto cats will address the diatoms really well, it's a temp phase anyway and it's extremely rare it will last more than say 2-3 weeks.
From there, you can modify the method to suit your routine.
I'd suggest testing months for NO3, and adjust as needed to target no more than 30ppm of NO3.
10-30ppm is a good target.

Check up on how to calibrate a test kit for NO3(see UKAPS).

I'd not worry much about PO4 etc, you can also learn, over time, how to eye ball the plant's health, and dose based more or less on that.
When that becomes tougher to figure, then you do the water change etc. Takes time to get good at it.

Regards,
Tom Barr

 

[SuperColey1]

The CO2 is not affected by KH/Ph. The Ph is affected by CO2 but not KH etc.

limestone will more than likely affect KH and Ph.

What happens is that if you have higher KH (not Ph) then CO2 will cause the Ph to drop by a leser amount for the same ppm of CO2. So if your KH was 8 before then your CO2 may drop the Ph by 0.8 for 30ppm. If your KH is now 12 then the Ph may drop by 0.4 for 30ppm. There is still the same ppm but it has lesser affect on the Ph. CO2 does not alter the KH it just alters the Ph. Therefore do not link Ph to KH too much. They can go hand in hand with each other but it is not always the case.

This is why the KH/PH table is far too inaccurate to use for CO2 methods and also why we use 4DKH in our DCs. 4DKH is ideal for a 1 point Ph drop and therefore we can see our colours much easier. Using tank water then you would have no idea in reality what the pm was.

Personally I would not have limestone in the tank unless you were intentionally trying to raise the POh from a very low acidic level.

AC

 

[aaronnorth]

The CO2 is not affected by KH/Ph. The Ph is affected by CO2 but not KH etc.

not unless you have a ridiculously high kH such as 30dkh, once it is high then CO2 cannot dissolve as easy.

 

[Spiceweasel69]

Didnt realise it was limestone (or alkili at any rate) Cheers for the info that makes sense to me now.