Auto dosing & Fert Choice

[tam]

I'm thinking of getting an auto doser. I'm just not very good at the routine of daily dosing manually and it seems a good solution. My duckweed is doing terribly and I know I'm chronically sort on nitrate! (I'm going to remove the duckweed while it's not fighting back in favour of frogbit).

I'm looking at the DD P1+ to do the dosing.

Currently I'm using tropica specialised, but I'm wondering if it would be safer to swap to TNC Complete? I know the tropica is urea based which is as I understand more of an issue if it accidently overdosed - not sure if I'm being paranoid it's the first time I'm used an autodoser. It's a low tech, rainwater with a splash of tap, very lightly stocked. Nothing is demanding, most growth is emersed and there is no CO2. I can't imagine it would make too much difference?

Also - do you need a fancy 'dosing' bottle or is there a reason you can't just drill a hole in the fertiliser lid and stuff the tube through?

Anything else I should consider for autodosers?

 

[ElleDee]

Have you tried front loading instead? Autodosers are very neat, but you may want to rule out your free and easy options first.

 

[Bradders]

Have you tried front loading instead? Autodosers are very neat, but you may want to rule out your free and easy options first.

OK, I'll bite. What is front loading?! Is that putting it all in as a weekly rather than daily?

 

[simon_the_plant_nerd]

OK, I'll bite. What is front loading?! Is that putting it all in as a weekly rather than daily?

You add the fertilisers when you do your water change. If you’re changing 50% weekly you would add to your water change the amount of fertiliser you need for a week for half the volume of your tank. If you only change 25% per week you would add a weeks worth of fertiliser for a quarter the volume of your tank. You can add more but I think you would risk accumulation of fertiliser or other chemicals not wanted in the water (which is the point of the water change in the first place).

You essentially remove the requirement to dose daily and just dose at water change. I’m new to all of this myself but the advantages I see is greater convenience and possibly greater stability in water parameters.

I’m not sure this would work for me though as my PH changes throughout the day due to CO2, any iron I add may precipitate out of solution before it’s used up so adding it daily when the PH is lower would be better.

EDIT: Phosphates are used in water treatment to remove metals and other contaminates. I think this would also contribute to iron and other micros not being available although I’m not sure if that’s going to happen in the quantities we dose into our tanks. Someone who knows a lot more than me will be able to explain it. 😄

 

[ElleDee]

It's pretty common to front load macros and do micros daily as @simon_the_plant_nerd does, but as long as your iron chelate is sufficient I think it's fine to do both, at least in low tech tanks because growth is slow/demand is low for micros. Plants have nutrient storage, scavenging, and substitution abilities to tide them over during brief periods without a particular nutrient, but in high energy tanks these tricks fall short more quickly because the demand for resources is greater and might reveal critical imbalances or shortfalls between water changes.

I'm not saying a micro deficiency is impossible in a low tech tank, but if you are using a complete fertilizer they are usually handled, excluding iron.

 

[tam]

I think my scedule is just not organised enough - my water changes probably average around 10 days but the gap isn't rigid, so calculating the percentage change and the time period would be tricky. I appreciate the thought though. I think the autodoser will keep a more stable base line even if it needs a manual extra splash based on plant health at water change.

I'd presume front loading would be better with TNC rather than tropica (urea) anyway. My tropica bottle is almost empty so I think I'm just going to switch for the piece of mind any way and then if I do want to top up at waterchange it works for that too.