Chiller Problem

[Gulls]

Am facing issues with cooling my Nano tank

I reside in India and am in a city which is hot and humid throughout the year. The room temperature is about 34 and the water temperature normally is about 31-32 degrees celcius.

 

My setup  details are as under:

I have two separate sumps with two chambers each.

The display overflows 40% of water to first sump holds macroalgae and DSB. It overflows to the second sump which hosts the chiller in the first chamber. 60% of the overflow from the display falls in the first chamber.

The return pump is placed in the second chamber of the second pump which received water post skimming. The return pump is a sicce silent 1.0 model which pushes about 900 lph to the Nano display Tank which is a 16 inch cube

 

 

The volume of water is as under:

Sump 1 chamber 1: 6 gallons net

Sump 1 chamber 2: 5 gallons net (sand level excluded)

 

Sump 2 chamber 1: 7 gallons net

Sump 2 chamber 2: 3 gallons net

 

Display volume (net): 15 gallons net water volume

 

I has a six footer aquarium previously (discontinued post relocation to another city) and a chiller for that size. Have a Hailea 1000B model suited for big aquariums. Am using the same chiller for this Nano set up

 

The chiller is oversized for this tank beyond doubt and chills the water within few minutes.

The chiller kicks on and cuts off way too frequently.

 

I am also facing challenges in maintaining the water temperature stable. The display, Sump 1 and the sump 2 all have different temperatures even post running the chiller for long time. The chamber where the chiller outlet is situated has the least temperature (chamber 1 sump 2)

The display had the maximum temperature with a variation of 0.7-1 degree celcius.

 

Please advise how I can have a uniform temperature across.

Is it the issue of an over-sized chiller cutting off and kicking on frequently?

Or is the matter of flow rate from chiller ? I am using a pump rated for 3000 litres per hour.

 

Will a smaller chilling unit provide uniformity and more stability?