Arduino Mega driving 6 relays problem

Hi, I am working on a project and I need to drive 6 relays that will turn on and off 6 solenoid valves. For some reason my Arduino fails to turn on all 6 relays ( and solenoid valves ) at the same time. Does anyone know what might cause this ? I was looking at all my specs and I feel like Arduino should be able to power all 6 at the same time, but it is just not the case here. It powers only 5 solenoid valves at the same time, but if I alternate and turn lets say 3 of them for 1 sec and then turn them off and power the rest of valves it works. I will provide links to parts that I am using below. Please also see attached photo for diagram.

Arduino board : https://www.amazon.com/gp/product/B00D9NA4CY/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Relays : https://www.amazon.com/gp/product/B00KTELP3I/ref=oh_aui_detailpage_o00_s03?ie=UTF8&psc=1

Solenoid valves: https://www.amazon.com/gp/product/B007N0DN3Q/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

Hi, Welcome to the forum.

Please read the first post in any forum entitled how to use this forum. http://forum.arduino.cc/index.php/topic,148850.0.html then look down to item #7 about how to post your code. It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

We need to see how you are driving the relays and how you are powering your project.

Thanks.. Tom.. :)

Use clickable links, don't make us copy and past.

Are you connected as in this diagram?

|500x275

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Ok, I solved my problem. Just in case if anyone else is going to need info, I am going to provide explanation to my problem.

This is my initial diagram

This is what I did, and it worked

I am new to electronics and still trying to figure out how everything works (I am Computer Scientist)
But I believe that previously Arduino was the one to provide power to drive the relays, and in 2nd diagram I am providing the voltage from external source.

I am not sure if this is how it works or not, but after making the change everything works for me.

Ok, I solved my problem.

Congratulations on you solving your problem ;)

If you look at the schematic I gave you in post #2 you see how to wire those relay boards.

You don't attach the Arduino GND to the relay board.

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If those solonoids are DC, you need kickback diodes across the solonoid coils, observe polarity!