Help choosing circulation pump

[Greenview]

I am new to planted tanks and grappling with the different equipment needed and the expense of it all. I am setting up Juwel Rio 180 litre and am about to order pressurised CO2 before I plant next week. I will retain the internal filter (it will come out in the future I expect) but I cannot afford to get a decent external in addition to all the other kit. I realise I will need to supplement the flow for CO2 distribution, I plan to put the CO2 low in the back left of the tank and have the filter outflow in the top right aiming across the tank. I thought that a Hydor Koralia Evolution pump aligned next to the filter outflow would help. I presume that a 2800lph pump is enough rather than a 4000.
I would appreciate advice as I am quite new to this. Thanks.

 

[niru]

Hi Greenview

I also have 180 Juwel with the internal filter retained. Though I have a not-so-powerful external as well mainly for spray bars with CO2 containing water (using Dupla reactor for adding CO2 to the outlet of the external filter), plus a Koralia nano for good circulation.

I have realised after watching my tank and reading a lot on UKAPS forums that if you plant heavily from the start, then the main chemical & biological filtration is assisted heavily by plants (& bacteria sitting on them). For your case, the internal filter should suffice for mechanical cleaning provided you have a good fine filter wool & other mechnical meshes/foams. In this case, there isnt much need of expensive filter mediums like sintered glass or other high-surface area pellets etc, since they mainly cater to bio/chem filtration. So use the internal filter mostly for mechanical cleaning and plant sufficiently heavily. Add the Koralia and you are doing fine.

Make sure that the Koralia flow assists the internal outlet flow directions. Plus since you plan a CO2, I guess it would be using a glass diffuser inside the tank that makes a lot of micro-bubbles' mist. Place this diffuser below the koralia so that the CO2 flows and mixes with all regions of the tank. You might have to tamper the Koralia & diffuser positions to ensure that the "other" end of the tank is also getting good flow.

Hope this helps.

-niru