Hi,

If I was to have a dodgy test kit which meant my tank was running at approx 74ppm CO2 what would be the effect on algae growth please?

Cheers

none, but your fish would hate you, then probably die unless you have very good surface agitation.

Also, any test kit is really dodgy, drop checkers are the only way of knowing fairly certainly how much co2 you actually have. The slightest misreading/inaccuracy on a test kit will yield results wildly all over the place, not to mention that testing your tank water isnt reliable due to the other things that can effect ph.

Thanks for your reply... The fish do hate me! I've been running 6.4PH with 6KH - had some loses, drop checker has shown light green

The reason for asking about algae is I have an algae problem of which I'm trying to find root cause, surely the amount of carbon produced, if not being utilised by the biomass would give algae an essential ingredient? I have a 1.5wpg...

Many thanks

make sure you have a good surface movement, i cant stress how important that is, and make sure your not adding co2 at night. those 2 things will mean you can add far more co2 safely during the photoperiod.

how are you dosing your tank? if your limiting your plants by a nutrient they wont grow, and the algae will as they need far less of the same things.

read the threads on the estimative index, and follow it as close as you can, and all your algae issues will likely go away. Its not going to be co2 thats causing it, its going to be a nutrient problem somewhere.

Thanks for the reply...

Ok, there is not much surface agitation, a 300pa Eheim pump is on the left of the tank positioned approx half way up the tank, it purpose to push the diffused CO2 around the mid back of the plants. The spray bar is at the top left and points diagonally (45dg) down towards the bottom of the tank. Are you suggesting surface agitation 24hrs?

Being low light, I'm dosing 2 x weekly 5ppm of KNO3 and 2 x weekly 5ml Flourish trace. Substrate is made up of laterite, Tetrapro complete and JBL floropol. When I see nitrates going up I dose 5ppm of K2SO4 - no K2HPO4 is added

I've read lots of threads on EI however cannot find any for the position I'm in with lighting etc... Any input would be great!

Not adding any PO4 is likely your issue. Plants need PO4 as much as they need CO2.

Follow the link in my sig to the nutrient calculater to work out what you need to be adding. For your lighting Id add 60% of what it tells you to, (Tom please correct me if Im wrong on that).

You need to provide everything the plants need, once your plants are growing well, they will outcompete the algae for resources and the algae will go.

Its a commonly stated misconception that PO4 causes algae.. limiting your plants growth by anything other than light is a large cause of algae.. algae is an opportunist beast, itll jump on any gaps in your maintinence/feeding schedules and exploit them.

In your garden outside, what happens if your plants arent growing well? They become stunted and unattractive, but also, weeds take over. Algae is just a weed.

Thanks... Would you agitate the surface 24hrs? If so, what's your feelings on CO2 loss overnight and PH drop? No hidden agenda here, I think its just a logical thing to do but there is some really bad press about it.

Now measuring phosphates...

agitate surface 24/7, you dont need to create waves, just a nice ripple, co2 loss is not much, and co2 is cheap as hell anyway. It gives your fish a rest during the night, and at night plants release co2 anyway. this will allow you to increase your co2 during the day considerably, for me its about double. so long as your fish are happy, theres no such thing as too much co2.

forget your test kits, measuring for any of those things is pretty hit and miss unles youve calibrated them and even then, well.. its hit and miss. the beauty of EI is that you dont need to measure, because your adding what you KNOW your plants are going to need.. when things are running nicely, adding more than you need isnt an issue either.. so testing becomes redundent.

Hi, I've repositioned the spray bar to create a ripple and will leave that 24/7

My phosphates are between 1 and 5ppm, agree about test kits. I've just measured out K2SO4 and KH2HPO4 and will look at dosing a third less than high light. Have just dosed sulphate/phosphate so fingers crossed!

Will be increasing CO2 rate over the next few days, live tester is reading green, PH 6.8 and KH6 so pretty much around the mark I think

The algae is a green hair / fuzz, then for some reason I get a massive amount of brown slimy algae - this related to a missing nutrient?

You have ok light, your reasonably sure you have ok co2, so the only thing it can be is nutrients dosing EI removes that option, and leaves you only co2 to worry about. life becomes much simpler then.